There is provided a polycarbonate resin composition containing aluminum oxide nanoparticles and being capable of showing good moldability and retention heat stability and combining high transparency and dimensional stability with excellent mechanical properties. The polycarbonate resin composition is characterized by containing an organic acid and aluminum oxide and in that: the resin composition has a melt mass flow rate of 11 g/10 min or higher as measured according to JIS K 7210 under the conditions of a temperature of 280° C., a nominal load of 2.16 Kg and a nozzle dimension UD of 8/2; and a No.2 dumbbell-shaped specimen according to JIS K 7113 formed by heat-press molding the resin composition into a film of 0.2 mm in thickness and cutting the film has a breaking stress of 8 MPa or higher as measured under the conditions of a temperature of 23° C., a humidity of 50% RH and a tensile rate of 50 min/min. The organic acid is preferably an organic sulfonic acid having a carbon number of 8 or greater, more preferably the one containing an aromatic ring in the molecule.