A polyphenylene sulfide resin composition including a polyphenylene sulfide resin having a specific amount of oligomers and a specific amount of a functional group, an amorphous thermoplastic resin having a glass transition temperature (Tg) of 120.degree. C. or higher, and an additive having a specific amount of a functional group. The moldings obtained from this polyphenylene sulfide resin composition have a good toughness (impact strength) and weld strength. The use of this polyphenylene sulfide resin composition as a material for secondary battery cases makes it possible to maintain the initial electrolytic performance over a long period of time.