A polyamide-polyphenylene ether based resin composition containing 1 to 20 mass ppm of copper and 0.1 to 2 mass % of titanium dioxide and/or carbon black, wherein a dispersed phase containing polyphenylene ether or polyphenylene ether and a partially hydrogenated block copolymer dispersed in the polyamide has a ratio of a volume average particle diameter to a number average particle diameter of the range of 2.0 to 5.0, and the polyphenylene ether in the resin composition has a weight average molecular weight of the range of 45,000 to 65,000.