the present invention is explained in detail with reference to the examples and comparative examples ; however , the present invention is not limited to the following examples . the materials shown below were used for preparation of the conductive layer a - forming paste composition and the conductive layer b - forming paste composition . conductive carbon particles : furnace black ( balkan xc72r : produced by cabot corporation ), average molecular weight : 1 , 000 to 3 , 000 , average particle diameter : 30 nm conductive carbon fibers ( 1 ): vgcf ( vgcf ( registered trademark ) ( standard product ): produced by showa denko k . k . ; average fiber diameter : 150 nm , average fiber length : 10 to 20 μm , and average aspect ratio : 10 to 500 ) conductive carbon fibers ( 2 ): s241 ( produced by osaka gas chemical , co ., ltd . ; average fiber diameter : 13 μm , average fiber length : 130 μm , and average aspect ratio : 10 ) polymer ( 1 ): nafion ( a 5 wt % nafion solution “ de - 520 ” produced by du pont , inc ., was used ), tg : 130 ° c . polymer ( 2 ): solef21216 / 1001 ( produced by solvay solexis ; pvdf ; solids content : 10 wt %), tg : − 30 ° c . polymer ( 3 ): polytetrafluoroethylene ( ptfe ) ( ad911l : produced by asahi glass co ., ltd . ), tg : about 130 ° c . conductive carbon particles ( 100 parts by weight ), polymer ( 3 ) ( 50 parts by weight ), conductive carbon fibers ( 1 ) ( 75 parts by weight ), polymer ( 1 ) ( 1 , 250 parts by weight ( solids content : 62 . 5 parts by weight )), dispersant ( 25 parts by weight ), and water ( 350 parts by weight ) were subjected to media dispersion to prepare a conductive layer a - forming paste composition . the conductive layer a - forming paste composition was applied to a polyethylene terephthalate ( pet ) film including a release layer to a thickness of about 50 μm using an applicator . regarding the viscosity of the paste composition , the shear viscosity was about 150 mpa · s at a shear rate of 1 , 000 ( 1 / s ). the viscosity of the paste composition was measured using a physica mcr301 produced by anton paar gmbh ( a cone - shaped jig with a diameter of 50 mm and an angle of 1 ° was used as a jig ). the paste compositions used in other examples and comparative examples were measured in the same manner . subsequently , drying was performed in a drying furnace set at 95 ° c . for about 15 minutes to produce a conductive layer ( a - 1 ). in the conductive layer ( a - 1 ), the polymers ( polymers ( 1 ) and ( 3 )) were present with a higher density at the surface in contact with the pet film . subsequently , the conductive layer ( a - 1 ) was detached from the pet film including the release layer , and the surface of the conductive layer ( a - 1 ) having the polymers ( polymers ( 1 ) and ( 3 )) with a higher density was brought into contact with the surface of a metal separator obtained by applying gold after the formation of a flow channel on a stainless steel substrate . hot - pressing was then performed at a pressing temperature of 120 ° c . and a pressing pressure of 15 kn , for a pressing time of 2 minutes to produce the laminate of example 1 . a conductive layer ( a - 1 ) was produced in the same manner as in example 1 . subsequently , the conductive layer ( a - 1 ) was detached from the pet film including the release layer , and the surface of the conductive layer ( a - 1 ) having the polymers ( polymers ( 1 ) and ( 3 )) with a higher density was brought into contact with the surface of carbon paper ( carbon paper tgph090 produced by toray industries , inc .). hot - pressing was then performed at a pressing temperature of 120 ° c . and a pressing pressure of 25 kn , for a pressing time of 2 minutes to produce the laminate of example 2 . polymer ( 2 ) was added to methyl ethyl ketone ( mek ), and the mixture was stirred at 80 ° c . for 60 minutes using a stirrer ( media rotation speed : 300 rpm ), thereby obtaining a pvdf solution having a solids content ( polymer ( 2 )) of 10 wt % in which polymer ( 2 ) was dissolved in the methyl ethyl ketone . conductive carbon fibers ( 2 ) ( 100 parts by weight ), the prepared pvdf solution having a solids content of 10 wt % ( 100 parts by weight ), and methyl ethyl ketone ( 50 parts by weight ) were subjected to media dispersion to prepare a conductive layer a - forming paste composition . the conductive layer a - forming paste composition was applied to a polyethylene terephthalate ( pet ) film including a release layer to a thickness of about 50 μm using an applicator . regarding the viscosity of the paste composition , the shear viscosity was about 437 mpa · s at a shear rate of 1 , 000 ( 1 / s ). subsequently , drying was performed in a drying furnace set at 95 ° c . for about 15 minutes to produce a conductive layer ( a - 2 ). in the conductive layer ( a - 2 ), the polymer ( polymer ( 2 )) was present with a higher density at the surface in contact with the pet film . subsequently , the conductive layer ( a - 2 ) was detached from the pet film including the release layer , and the surface of the conductive layer ( a - 2 ) having the polymer ( polymer ( 2 )) with a higher density was brought into contact with the surface of a metal separator obtained by applying gold after the formation of a flow channel on a stainless steel substrate . hot - pressing was then performed at a pressing temperature of 150 ° c . and a pressing pressure of 100 kn , for a pressing time of 2 minutes to produce the laminate of example 3 . a conductive layer ( a - 2 ) was produced in the same manner as in example 3 . subsequently , the conductive layer ( a - 2 ) was detached from the pet film including the release layer , and the surface of the conductive layer ( a - 2 ) having the polymer ( polymer ( 2 )) with a higher density was brought into contact with the surface of carbon paper ( carbon paper tgph090 produced by toray industries , inc .). hot - pressing was then performed at a pressing temperature of 150 ° c . and a pressing pressure of 100 kn , for a pressing time of 2 minutes to produce the laminate of example 4 . conductive carbon particles ( 100 parts by weight ), polymer ( 3 ) ( 50 parts by weight ), conductive carbon fibers ( 1 ) ( 75 parts by weight ), polymer ( 1 ) ( 1 , 250 parts by weight ( solids content : 62 . 5 parts by weight )), dispersant ( 25 parts by weight ), and water ( 350 parts by weight ) were subjected to media dispersion to prepare a conductive layer b - forming paste composition . the conductive layer b - forming paste composition was applied to a polyethylene terephthalate ( pet ) film including a release layer to a thickness of about 50 μm using an applicator . regarding the viscosity of the paste composition , the shear viscosity was about 150 mpa · s at a shear rate of 1 , 000 ( 1 / s ). thereafter , drying was performed in a drying furnace set at 95 ° c . for about 15 minutes to produce a conductive layer ( b - 1 ). in the conductive layer ( b - 1 ), the polymers ( polymers ( 1 ) and ( 3 )) were present with a higher density at the surface in contact with the pet film . the conductive layer ( b - 1 ) produced was the same as the conductive layer ( a - 1 ) produced in example 1 . the surface opposite to the surface of the conductive layer ( b - 1 ) having the polymers ( polymers ( 1 ) and ( 3 )) with a higher density was brought into contact with the surface of the conductive layer ( a - 1 ) of the laminate produced in example 1 , and hot - pressing was performed at a pressing temperature of 120 ° c . and a pressing pressure of 100 kn , for a pressing time of 2 minutes to produce the laminate of example 5 . the surface opposite to the surface of the conductive layer ( b - 1 ) having the polymers ( polymers ( 1 ) and ( 3 )) with a higher density was brought into contact with the surface of the conductive layer ( a - 1 ) of the laminate produced in example 2 , and hot - pressing was then performed at a pressing temperature of 120 ° c . and a pressing pressure of 100 kn , for a pressing time of 2 minutes to produce the laminate of example 6 . the laminate of comparative example 1 was produced in the same manner as in example 1 except that the conductive layer ( a - 1 ) was detached from the pet film including the release layer , the surface opposite to the surface of the conductive layer ( a - 1 ) having the polymers ( polymers ( 1 ) and ( 3 )) with a higher density was brought into contact with the surface of a metal separator obtained by applying gold after the formation of a flow channel on a stainless steel substrate , and hot - pressing was performed at a pressing temperature of 120 ° c . and a pressing pressure of 15 kn , for a pressing time of 2 minutes . the laminate of comparative example 2 was produced in the same manner as in example 2 except that the conductive layer ( a - 1 ) was detached from the pet film including the release layer , the surface opposite to the surface of the conductive layer ( a - 1 ) having the polymers ( polymers ( 1 ) and ( 3 )) with a higher density was brought into contact with the surface of carbon paper ( carbon paper tgph090 produced by toray industries , inc . ), and hot - pressing was performed at a pressing temperature of 120 ° c . and a pressing pressure of 25 kn , for a pressing time of 2 minutes . the laminate of comparative example 3 was produced in the same manner as in example 3 except that the conductive layer ( a - 2 ) was detached from the pet film including the release layer , the surface opposite to the surface of the conductive layer ( a - 2 ) having the polymer ( polymer ( 2 )) with a higher density was brought into contact with the surface of a metal separator obtained by applying gold after the formation of a flow channel on a stainless steel substrate , and hot - pressing was performed at a pressing temperature of 150 ° c . and a pressing pressure of 100 kn , for a pressing time of 2 minutes . the laminate of comparative example 4 was produced in the same manner as in example 4 except that the conductive layer ( a - 2 ) was detached from the pet film including the release layer , the conductive layer ( a - 2 ) having the polymer ( polymer ( 2 )) with a higher density was brought into contact with the surface opposite to the surface of carbon paper ( carbon paper tgph090 produced by toray industries . inc . ), and hot - pressing was performed at a pressing temperature of 150 ° c . and a pressing pressure of 100 kn , for a pressing time of 2 minutes . 4 g of platinum catalyst - supporting carbon particles (“ tec10e50e ” produced by tanaka kikinzoku kogyo ), 40 g of an ion - conductive polymer electrolyte solution ( nafion 5 wt % solution : “ de - 520 ” produced by du pont , inc . ), 12 g of distilled water , 20 g of n - butanol , and 20 g of t - butanol were added , and mixed while being stirred using a disperser , thereby obtaining an anode catalyst layer - forming paste composition and a cathode catalyst layer - forming paste composition . the anode catalyst layer - forming paste composition and the cathode catalyst layer - forming paste composition were each individually applied to a transfer substrate ( material : polyethylene terephthalate film ) using an applicator , and dried at 95 ° c . for 30 minutes to form catalyst layers , thereby obtaining an anode catalyst layer - forming transfer sheet and a cathode catalyst layer - forming transfer sheet . the coating amount of the catalyst layer was determined so that both of the anode catalyst layer and the cathode catalyst layer had a platinum - supporting amount of about 0 . 45 mg / cm 2 . using the anode catalyst layer - forming transfer sheet and the cathode catalyst layer - forming transfer sheet produced above , hot - pressing was performed on front and back surfaces of the electrolyte membrane ( nafion membrane “ nr - 212 ” produced by du pont , inc . ; film thickness : 50 μm ) at 135 ° c . and 5 mpa for 2 minutes , and then each of the transfer substrates alone was detached . the catalyst layer laminated membrane was thus produced . two laminates produced according to example 5 were prepared . the laminates were disposed in a manner such that the conductive layer ( b - 1 ) side surface of each laminate was in contact with each of the catalyst layer surfaces of the catalyst layer laminated membrane obtained in reference example 1 . hot pressing was performed at a pressing temperature of 100 ° c ., pressing pressure of 7 . 5 kn , and pressing time of 2 minutes , and the solid polymer fuel cell of example 7 was thus produced . two laminates produced according to example 1 were prepared . two conductive layers ( b - 1 ) produced according to example 5 were also prepared . each conductive layer ( b - 1 ) was detached from the pet film including the release layer , and the surface of the conductive layer ( b - 1 ) having the polymers ( polymers ( 1 ) and ( 3 )) with a higher density was brought into contact with each side of the catalyst layer laminated membrane obtained in reference example 1 . hot pressing was performed at a pressing temperature of 100 ° c ., pressing pressure of 7 . 5 kn , and pressing time of 2 minutes to produce a laminate in which the conductive layer ( b - 1 ) was formed on both sides of the catalyst layer laminated membrane . subsequently , the laminates obtained according to example 1 were disposed in a manner such that the conductive layer ( a - 1 ) side surface of each laminate was in contact with each of the conductive layers ( b - 1 ) of the laminate produced , and the laminates were stacked to produce the solid polymer fuel cell of example 8 . the membrane - electrode assembly of example 9 was produced in the same manner as in example 8 except that the laminate produced in example 2 was used in place of the laminate produced in example 1 . the solid polymer fuel cell of example 10 was produced in the same manner as in example 8 except that the laminate produced in example 3 was used in place of the laminate produced in example 1 . the membrane - electrode assembly of example 11 was produced in the same manner as in example 8 except that the laminate produced in example 4 was used in place of the laminate produced in example 1 . the conductive layer a - forming paste composition , which was the same as the paste in example 3 , was prepared . regarding the viscosity of the paste composition , the shear viscosity was about 437 mpa · s at a shear rate of 1 , 000 ( 1 / s ). the conductive layer a - forming paste composition was applied to a polyethylene terephthalate ( pet ) film including the release layer , using an applicator to a thickness of about 50 μm . immediately thereafter , hot air set at 80 ° c . was applied to the coating side for drying to produce a conductive layer ( a - 3 ). in the conductive layer ( a - 3 ), the polymer ( polymer ( 2 )) was present with a higher density at the surface in contact with the pet film . subsequently , the laminate of example 12 was produced in the same manner as in example 3 except that the conductive layer ( a - 2 ) was detached from the pet film including the release layer , the surface of the conductive layer ( a - 2 ) having the polymer ( polymer ( 2 )) with a higher density was brought into contact with the surface of a metal separator to which gold had been applied after the formation of a flow channel of a stainless steel plate , and hot - pressing was performed at a pressing temperature of 150 ° c . and a pressing pressure of 25 kn , for a pressing time of 2 minutes . the conductive layer ( a - 3 ) was produced in the same manner as in example 12 . the laminate of comparative example 5 was produced in the same manner as in example 3 except that the conductive layer ( a - 3 ) was detached from the pet film including the release layer , the surface opposite to the surface of the conductive layer ( a - 3 ) having the polymer ( polymer ( 2 )) with a higher density was brought into contact with the surface of a metal separator obtained by applying gold after the formation of a flow channel on a stainless steel substrate , and hot - pressing was performed at a pressing temperature of 150 ° c . and a pressing pressure of 25 kn , for a pressing time of 2 minutes . the conductive layer ( a - 3 ) was produced in the same manner as in example 12 . subsequently , the conductive layer ( a - 3 ) was detached from the pet film including the release layer , the surface of the conductive layer ( a - 3 ) having the polymer ( polymer ( 2 )) with a higher density was brought into contact with the surface of carbon paper ( carbon paper tgph090 produced by toray industries . inc . ), and hot - pressing was performed at a pressing temperature of 150 ° c . and a pressing pressure of 25 kn , for a pressing time of 2 minutes , thus obtaining the laminate of example 13 . the conductive layer ( a - 3 ) was produced in the same manner as in example 12 . subsequently , the conductive layer ( a - 3 ) was detached from the pet film including the release layer , the surface that was opposite to the surface of the conductive layer ( a - 3 ) having the polymer ( polymer ( 2 )) with a higher density was brought into contact with the surface of carbon paper ( carbon paper tgph090 produced by toray industries . inc . ), and hot - pressing was performed at a pressing temperature of 150 ° c . and a pressing pressure of 25 kn , for a pressing time of 2 minutes , thus obtaining the laminate of comparative example 6 . the conductive layer ( a - 1 ) obtained in example 1 , the conductive layer ( a - 2 ) obtained in example 3 , and the conductive layer ( a - 3 ) obtained in example 12 were each detached from the pet film including the release layer . the layers were observed by energy dispersion x - ray analysis . table 1 shows the results . as the analysis device , an ex - 23000bu energy dispersion x - ray analysis device produced by jeol ltd ., was used . the results confirmed that the density of the f element contained in the polymer was different between the front surface and the back surface of each conductive layer ; and the polymer was segregated between the front surface and the back surface of the conductive layer a . in table 1 , “ pet film contact surface ” means the surface that was in contact with the pet film before the pet film was detached from the conductive layer a , and “ pet film non - contact surface ” means the surface opposite to the pet film contact surface . using a medium - temperature press device ( produced by tester sangyo , co ., ltd . ), adhesion between the conductive layer ( a - 1 ), ( a - 2 ), or ( a - 3 ) and the metal separator or conductive porous substrate in each of the laminates ( 50 × 50 mm 2 ) obtained in examples 1 to 6 and 12 to 13 , and comparative examples 1 to 6 , was measured . adhesion was subjectively evaluated as to whether layers were adhered together in a manner such that one layer was not detached from another layer . specifically , adhesion was rated a or b . b : easy to detach layers with hands , or no adhesion observed . table 2 shows the results .