To obtain a resin composition excellent in mold releasability and moldability in spite of a styrene-based resin and a polyphenylene ether-based resin contained as principal components.

This flame retardant styrene-based resin composition is prepared by including (C) 0.1-1 pts.wt. of a polyethylene wax and (D) 5-20 pts.wt. of an oligomer type aromatic phosphoric ester in 100 pts.wt. of a resin composition comprising (A) a styrene-based resin containing at least a rubber-modified styrene-based resin and (B) a polyphenylene ether-based resin in (80/20) to (95/5) weight ratio of the components (A)/(B). The resultant flame retardant styrene- based resin composition is used as a molding material, etc., for a toner cartridge container.