A method for producing a foam-molded body of a resin composition comprising a step of foam-molding said resin composition by means of injection foaming involving expansion of a cavity using a foaming agent, said resin composition containing a polycarbonate copolymer having a structural unit derived from a dihydroxy compound represented by the following formula: and a structural unit derived from other dihydroxy compounds, and having a glass transition temperature (Tg) of less than 145°C, wherein the ratio of the structural unit derived from a dihydroxy compound represented by formula to the structural units derived from all dihydroxy compounds contained in the polycarbonate copolymer is from 30 to 90 mol%, wherein the structural unit derived from other dihydroxy compounds is at least one structural unit selected from the group consisting of a structural unit derived from a dihydroxy compound represented by the following formula: HO-R 1 -OH wherein R 1 represents a substituted or unsubstituted cycloalkylene group having a carbon number of 4 to 20, a structural unit derived from a dihydroxy compound represented by the following formula: HO-CH 2 -R 2 -CH 2 -OH wherein R 2 represents a substituted or unsubstituted cycloalkylene group having a carbon number of 4 to 20, a structural unit derived from a dihydroxy compound represented by the following formula: H-(O-R 3) P -OH wherein R 3 represents a substituted or unsubstituted alkylene group having a carbon number of 2 to 10, and p is an integer of 2 to 50, and a structural unit derived from a dihydroxy compound represented by the following formula: HO-R 4 -OH wherein R 4 represents a substituted or unsubstituted alkylene group having a carbon number of 2 to 20 or a group containing a substituted or unsubstituted acetal ring, wherein the timing of starting expansion of the cavity is within 0.1 seconds before or after the completion of filling; and wherein the foaming agent is an inorganic gas. and a structural unit derived from other dihydroxy compounds, and having a glass transition temperature (Tg) of less than 145°C, wherein the ratio of the structural unit derived from a dihydroxy compound represented by formula to the structural units derived from all dihydroxy compounds contained in the polycarbonate copolymer is from 30 to 90 mol%, wherein the structural unit derived from other dihydroxy compounds is at least one structural unit selected from the group consisting of a structural unit derived from a dihydroxy compound represented by the following formula: HO-R 1 -OH wherein R 1 represents a substituted or unsubstituted cycloalkylene group having a carbon number of 4 to 20, a structural unit derived from a dihydroxy compound represented by the following formula: HO-CH 2 -R 2 -CH 2 -OH wherein R 2 represents a substituted or unsubstituted cycloalkylene group having a carbon number of 4 to 20, a structural unit derived from a dihydroxy compound represented by the following formula: H-(O-R 3) P -OH wherein R 3 represents a substituted or unsubstituted alkylene group having a carbon number of 2 to 10, and p is an integer of 2 to 50, and a structural unit derived from a dihydroxy compound represented by the following formula: HO-R 4 -OH wherein R 4 represents a substituted or unsubstituted alkylene group having a carbon number of 2 to 20 or a group containing a substituted or unsubstituted acetal ring, wherein the timing of starting expansion of the cavity is within 0.1 seconds before or after the completion of filling; and wherein the foaming agent is an inorganic gas.