A resin composition comprising: a bisphenol AP type polycarbonate resin having a viscosity average molecular weight of 18,500 to 23,000; and a bisphenol A type polycarbonate resin having a viscosity average molecular weight of 25,000 to 35,000, wherein a ratio W AP /W A of a mass W AP of the bisphenol AP type polycarbonate resin to a mass W A of the bisphenol A type polycarbonate resin is 20/80 to 90/10, a difference |η AP - η A | between an intrinsic viscosity η AP of the bisphenol AP type polycarbonate resin and an intrinsic viscosity η A of the bisphenol A type polycarbonate resin is 0.04 to 0.18 dL/g, and wherein the total content of the bisphenol AP type polycarbonate resin and the bisphenol A type polycarbonate resin is 95% by mass or more based on the total amount of resin components contained in the resin composition, wherein bisphenol AP type polycarbonate has a constituent unit represented by the following formula (A-1): wherein R 1 to R 4 each independently represent a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group having 1 to 9 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an aralkyl group having 7 to 17 carbon atoms, l represents an integer of 0 to 5, m and n each independently represent an integer of 0 to 4 and * represents an end group or a bonding position with another constituent unit, and wherein bisphenol A type polycarbonate has a constituent unit represented by the following formula (B-1): wherein X 1 represents the following structure: wherein R 5 and R 6 are each a hydrogen atom or a methyl group, wherein a specific viscosity η sp at each solution concentration C is measured with an Ubbelohde viscometer at 25°C using methylene chloride as the solvent, and the intrinsic viscosity η is calculated from the obtained value of the specific viscosity η sp and the concentration C according to the following formula: η = lim c → 0 η sp / c, and wherein the viscosity average molecular weight Mv is calculated according to Schnell's viscosity equation: η = 1.23 × 10 − 4 Mv 0.83. a bisphenol AP type polycarbonate resin having a viscosity average molecular weight of 18,500 to 23,000; and a bisphenol A type polycarbonate resin having a viscosity average molecular weight of 25,000 to 35,000, wherein a ratio W AP /W A of a mass W AP of the bisphenol AP type polycarbonate resin to a mass W A of the bisphenol A type polycarbonate resin is 20/80 to 90/10, a difference |η AP - η A | between an intrinsic viscosity η AP of the bisphenol AP type polycarbonate resin and an intrinsic viscosity η A of the bisphenol A type polycarbonate resin is 0.04 to 0.18 dL/g, and wherein the total content of the bisphenol AP type polycarbonate resin and the bisphenol A type polycarbonate resin is 95% by mass or more based on the total amount of resin components contained in the resin composition, wherein bisphenol AP type polycarbonate has a constituent unit represented by the following formula (A-1): wherein R 1 to R 4 each independently represent a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group having 1 to 9 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an aralkyl group having 7 to 17 carbon atoms, l represents an integer of 0 to 5, m and n each independently represent an integer of 0 to 4 and * represents an end group or a bonding position with another constituent unit, and wherein bisphenol A type polycarbonate has a constituent unit represented by the following formula (B-1): wherein X 1 represents the following structure: wherein R 5 and R 6 are each a hydrogen atom or a methyl group, wherein a specific viscosity η sp at each solution concentration C is measured with an Ubbelohde viscometer at 25°C using methylene chloride as the solvent, and the intrinsic viscosity η is calculated from the obtained value of the specific viscosity η sp and the concentration C according to the following formula: η = lim c → 0 η sp / c, and wherein the viscosity average molecular weight Mv is calculated according to Schnell's viscosity equation: η = 1.23 × 10 − 4 Mv 0.83.