To provide a case for a portable telephone which has sufficient waterproofness, does not hinder input and output of speech and does not degrade the operability of push buttons even in winter or in cold districts.

This case for the portable telephone is formed by sealing the three sides of two films having an approximately rectangular shape and freely hermetically opening the remaining one side and has capacity to allow housing the portable telephone therein. The one film is a polyurethane elastomer film which is transparent or translucent and has a thickness of 30 μm to 0.2 mm and the other film is a polyurethane elastomer film which may be opaque.