A thermoplastic resin composition that contains, based on 100 mass parts for a total of (A) and (B), at least 20 mass parts but less than 50 mass parts of (A) a polyalkylene terephthalate resin and more than 50 mass parts and not more than 80 mass parts of (B) a polystyrene resin or a rubber-reinforced polystyrene resin, wherein an intrinsic viscosity (IVA) of the polyalkylene terephthalate resin (A) is 0.3 to 0.8 dl/g and a melt viscosity (ηB) of the polystyrene resin or rubber-reinforced polystyrene resin (B) at 250° C. and 912 sec−1 is at least 80 Pa·sec.