now , an embodiment of method of assembling a vehicle body panel member according to the present invention will be described in detail with reference to the accompanying drawings hereinafter . in the case where a body side panel member used for constituting a vehicle body is assembled in accordance with an example of the method according to the present invention , first , as shown in fig1 a , a front pillar outer component 10 , a rear fender component 12 and a side sill component 14 are arranged to be stationary at respective predetermined positions . then , a connecting portion 10a of the front pillar outer component 10 and a connecting portion 12a of the rear fender component 12 are coupled with each other by means of spot welding , a connecting portion 10b of the front pillar outer component 10 and a connecting portion 14a of the side sill component 14 are coupled with each other by means of spot welding , and a connecting portion 12b of the rear fender component 12 and a connecting portion 14b of the side sill component 14 are coupled with each other by means of spot welding , so that the front pillar outer component 10 , rear fender component 12 and side sill component 14 are incorporated into an outer panel 15 which is used for forming the exterior of the vehicle body , as show in fig1 b . next , mig welding is carried out at a junction r between the front pillar outer component 10 and the rear fender component 12 , at which the connecting portions 10a and 12a are welded with each other and which appears on the external surface of the outer panel 15 , as shown in fig1 b . after the mig welding provided at the junction r on the external surface of the outer panel 15 , a center pillar inner component 30 , a rear pillar inner component 31 and a front pillar inner component 32 , as shown in fig1 c , are connected by means of spot welding with the front pillar outer component 10 and the rear fender component 12 forming the outer panel 15 so as to form an inner panel disposed on the inside of the outer panel 15 , so that a body side panel member 35 is formed with the outer panel 15 and the inner panel connected with the outer panel 15 to be disposed on the inside of the outer panel 15 , as shown in fig1 d . each of the center pillar inner component 30 and the front pillar inner component 32 is coupled with the outer panel 15 so as to have a portion thereof positioned on the inside of a portion of the outer panel 15 at which the junction r is formed . fig2 shows an example of a welding station in which the outer panel 15 is subjected to the mig welding provided at the junction r on its external surface . in the station shown in fig2 the outer panel 15 is carried therein by a lifter 25 and shifted from the lifter 25 to be put on supporting stands 21 , 22 , 23 and 24 due to descent of the lifter 25 . the outer panel 15 put on the supporting stands 21 to 24 has its external surface facing downward and is fixed on the supporting stands 21 to 24 by clamping devices 26 and 27 including driving cylinders 26a and 27a respectively . the clamping device 27 is operative to secure the connecting portion 10a of the front pillar outer component 10 and the connecting portion 12a of the rear fender component 12 which have been welded with each other to form the junction r on the external surface of the outer panel 15 . when the connecting portions 10a and 12a are actually secured by the clamping device 27 , the external surface of the connecting portion 10 a and the external surface of the connecting portion 12a are supported by a top surface of the supporting stand 24 , which is shaped to fit the external surfaces of the connecting portions 10a and 12a , and the internal surface of the connecting portion 10a and the internal surface of the connecting portion 12a are pressed down by an end portion 27b of the clamping device 27 , which is shaped to fit the internal surfaces of the connecting portions 10a and 12a and caused by the driving cylinder 27a to come into contact with the internal surfaces of the connecting portions 10a and 12a for pushing the connecting portions 10a and 12a toward the top surface of the supporting stand 24 . after the outer panel 15 is fixed by the clamping devices 26 and 27 , a welding electrode device 29 which is supported by an arm 28a of a robot 28 is caused to face the junction r formed on the external surface of the outer panel 15 by the connecting portion 10a of the front pillar outer component 10 and the connecting portion 12a of the rear fender component 12 , and the mig welding is provided on the junction r by the welding electrode device 29 . during the mig welding thus carried out at the junction r , the end portion 27b of the clamping device 27 is easily and surely in contact with the internal surfaces of the connecting portions 10a and 12a , as shown in fig3 and therefore the connecting portion 10a of the front pillar outer component 10 and the connecting portion 12a of the rear fender component 12 forming the junction r on the external surface of the outer panel 15 are secured sufficiently so that the mig welding at the junction r is properly carried out and the outer panel 15 is prevented from being undesirably deformed with heat resulting from the mig welding . fig4 shows another example of the welding station in which the outer panel 15 is subjected to the mig welding provided at the junction r on its external surface . in the station shown in fig4 the outer panel 15 is carried by a lifter 40 and shifted from the lifter 40 to be temporarily put on supporting stands 41 and 42 due to descent of the lifter 40 , as shown with dot - dash lines in fig4 . the outer panel 15 temporarily put on the supporting stands 41 and 42 has its external surface facing downward . then , a movable frame 43 which is provided with holding devices 44 and 45 and operative to be rotated by a motor 46 is rotated clockwise to be positioned above the outer panel 15 temporarily put on the supporting stands 41 and 42 , as shown with dot - dash lines in fig4 . the holding devices 44 and 45 are operative to contact with the outer panel 15 for holding the same firmly . especially , the holding device 45 is operative to secure the connecting portion 10a of the front pillar outer component 10 and the connecting portion 12a of the rear fender component 12 which have been welded with each other to form the junction r on the external surface of the outer panel 15 . the movable frame 43 provided with the holding devices 44 and 45 holding the outer panel 15 is rotated counterclockwise , together with the outer panel 15 , by the motor 46 to be supported to become stationary by a supporting structure 47 as shown with solid lines in fig4 and on that occasion , the outer panel 15 is held by the holding devices 44 and 45 provided on the movable frame 43 so as to have its external surface facing upward . as shown in fig5 the holding device 44 comprises a base 50 fixed to the movable frame 43 and provided thereon with panel receiving portions 51 and 52 , a first movable clamper 53 having a driving cylinder 53a and mounted on the base 50 and a second movable clamper 54 having a driving cylinder 54a and mounted also on the base 50 . when the outer panel 15 is actually held by the holding device 44 , a portion of the rear fender component 12 forming the outer panel 15 is received on the inside thereof by the panel receiving portions 51 and 52 provided on the base 50 and clamped from the outside thereof by the first and second movable clampers 53 and 54 driven by the driving cylinders 53a and 54a respectively . further , as shown in fig6 the holding device 45 comprises a base 55 fixed to the movable frame 43 , a movable panel receiver 56 mounted to be rotatable on the base 55 and having a panel receiving surface 56a and a driving cylinder 56b secured to the base 55 , and a movable clamper 57 mounted to be rotatable on the base 55 and having a panel pushing surface 57a , a slit 57b and a driving cylinder 57c secured to the base 55 . when the connecting portion 10a of the front pillar outer component 10 and the connecting portion 12a of the rear fender component 12 forming the junction r on the external surface of the outer panel 15 is actually secured by the holding device 45 , the movable panel receiver 56 is rotated counterclockwise by the driving cylinder 56b to cause the panel receiving surface 56a to come into contact with both the internal surface of the connecting portion 10a and the internal surface of the connecting portion 12a . the panel receiving surface 56a is shaped to fit the internal surfaces of the connecting portions 10a and 12a . then , the movable clamper 57 is rotated clockwise by the driving cylinder 57c to cause the panel pushing surface 57a to come into contact with both the external surface of the connecting portion 10a and the external surface of the connecting portion 12a for pushing the connecting portions 10a and 12a toward the panel receiving surface 56a of the movable panel receiver 56 . the panel pushing surface 57a is shaped to fit the external surfaces of the connecting portions 10a and 12a . after the movable frame 43 is positioned to be supported by the supporting structure 47 , together with the outer panel 15 which is secured by the holding device 44 and 45 , as shown with solid lines in fig4 a welding electrode device 58 which is supported by an arm 59a of a robot 59 is caused to face the junction r formed on the external surface of the outer panel 15 by the connecting portion 10a of the front pillar outer component 10 and the connecting portion 12a of the rear fender component 12 , through the slit 57b provided on the movable clamper 57 as shown in fig6 and the mig welding is provided on the junction r by the welding electrode device 58 . in such a case , during the mig welding thus carried out at the junction r , the panel receiving surface 56a of the movable panel receiver 56 and the panel pushing surface 57a of the movable clamper 57 both provided on the holding device 45 are surely in contact with the internal surfaces and the external surfaces of the connecting portions 10a and 12a , respectively , as shown in fig3 and therefore the connecting portion 10a of the front pillar outer component 10 and the connecting portion 12a of the rear fender component 12 forming the junction r on the external surface of the outer panel 15 are secured sufficiently so that the mig welding at the junction r is properly carried out and the outer panel 15 is prevented from being undesirably deformed with heat resulting from the mig welding . although , in the above described embodiment , the body side panel member is assembled in accordance with one example of the method according to the present invention , the method according to the present invention in applicable also for assembling various vehicle body panel members other than the body side panel member .