A polycarbonate-based resin composition, comprising: 100 parts by mass of a resin mixture formed of: 30 to 100 mass% of a polycarbonate-polyorganosiloxane copolymer (A-1) which has a constituent unit represented by a general formula and a constituent unit represented by a general formula, and in which an average repetition number n of organosiloxane constituent units in the general formula is 70 to 500; and 70 to 0 mass% of an aromatic polycarbonate resin (A-2) except the polycarbonate-polyorganosiloxane copolymer (A-1); 0.01 to 0.15 part by mass of an alkaline metal salt and/or alkaline earth metal salt of an organic sulfonic acid; 0.1 to 1 part by mass of a polytetrafluoroethylene having a fibril-forming ability; and 2 to 15 parts by mass of titanium dioxide particles each having, on an outermost surface thereof, a coating layer formed of a polyol free of a nitrogen atom: in the formula, R 1 and R 2 each independently represent an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, X represents a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, -S-, -SO-, -SO 2 -, -O-, or -CO-, and a and b each independently represent an integer of 0 to 4, and in the formula, R 3 to R 6 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, Y represents an organic residue containing an aliphatic or aromatic group, and n represents the average repetition number. 100 parts by mass of a resin mixture formed of: 30 to 100 mass% of a polycarbonate-polyorganosiloxane copolymer (A-1) which has a constituent unit represented by a general formula and a constituent unit represented by a general formula, and in which an average repetition number n of organosiloxane constituent units in the general formula is 70 to 500; and 70 to 0 mass% of an aromatic polycarbonate resin (A-2) except the polycarbonate-polyorganosiloxane copolymer (A-1); 30 to 100 mass% of a polycarbonate-polyorganosiloxane copolymer (A-1) which has a constituent unit represented by a general formula and a constituent unit represented by a general formula, and in which an average repetition number n of organosiloxane constituent units in the general formula is 70 to 500; and 70 to 0 mass% of an aromatic polycarbonate resin (A-2) except the polycarbonate-polyorganosiloxane copolymer (A-1); 0.01 to 0.15 part by mass of an alkaline metal salt and/or alkaline earth metal salt of an organic sulfonic acid; 0.1 to 1 part by mass of a polytetrafluoroethylene having a fibril-forming ability; and 2 to 15 parts by mass of titanium dioxide particles each having, on an outermost surface thereof, a coating layer formed of a polyol free of a nitrogen atom: in the formula, R 1 and R 2 each independently represent an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, X represents a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, -S-, -SO-, -SO 2 -, -O-, or -CO-, and a and b each independently represent an integer of 0 to 4, and in the formula, R 3 to R 6 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, Y represents an organic residue containing an aliphatic or aromatic group, and n represents the average repetition number.