the present invention relates to a method for producing a foamed article by which a foamed article having a high expansion ratio , having uniform fine cells in a high closed cell ratio and capable of being recycled , which is utilizable as heat insulating materials for construction , cushioning materials for wrapping , cushioning floats for ships , floats for sports and leisure and the like , can be obtained readily and safely using a clean inorganic gas as a foaming agent , and to a foamed article obtained by the method . that is , the present invention provides a method for producing a foamed resin article comprising a melting step of feeding a thermoplastic resin into an extruder and heating it to melt , a kneading step of mixing an inorganic gas with the thermoplastic resin in the extruder to produce a kneaded material , and a foaming step of discharging the kneaded material from a mold having a tubular channel mounted to the end of the extruder to form the foamed article , wherein extrusion molding is carried out within the range where a numeric x , which is defined by the following expression : x = 100 p + 3 . 5 h where a resin feeding pressure of the thermoplastic resin from the extruder to the mold is represented by h and an expansion ratio is represented by p , and the resin feeding pressure h satisfy the following expressions simultaneously : 780 ≦ x ≦ 4000 , and 80 ≦ h ≦ 1000 and the like .