To provide a case having a high electrolyte resistant characteristic, ensuring a good balance between moldability and heat resistance, and further having good appearance by forming the case out of polyphenylene ether resin composition containing the prescribed amount of polyolefine.

A battery case used for housing at least one organic electrolyte battery is formed out of polyphenylene ether resin composition. The composition in this case is made to contain an amount of polyolefine between 0.1wt.% and 4.0wt.%. As a result, the organic electrolyte resistant characteristic of the battery housing case is further improved. Also, the battery housing case comes to have a good balance between thin-walled moldability and heat resistance, good appearance and high flame resistance.