Provided is a polyphenylene ether resin composition having excellent mechanical properties, such as tensile, flexural, and impact strength, high flame retardance, and adequate molding fluidity, and that is sufficiently resistant to use as a thin molded article for an electric/electronic device cooling fan, etc. The polyphenylene ether resin composition contains at least 90 mass % of a polyphenylene ether (A), a styrene resin (B), glass fiber (C), and an organophosphorus flame retardant (D) in terms of total mass of (A) to (D). Taking this total mass as 100 mass %, contents of the polyphenylene ether (A), styrene resin (B), glass fiber (C), and organophosphorus flame retardant (D) are 25-75 mass %, 0-5 mass %, 20-50 mass %, and 5-20 mass %, respectively, and taking mass of the organophosphorus flame retardant (D) as 100 mass %, content of at least one compound selected from the group consisting of triphenyl phosphate and a phosphazene is at least 70 mass %.