Abstract: An adapter for a plug receptacle provided with a pair of plug terminals is capable of being fitted in various kinds of plug receptacles. A pair of adapter bodies made of an insulating material are pivotally connected at a lower portion thereof to each other. The adapter bodies each have a plug terminal provided on a front end surface of a corresponding one thereof and adapted to be inserted into a corresponding one of power terminal holes of a plug receptacle. Also, one of the adapter bodies is provided with a pair of power terminal holes having terminal contacts for a plug receptacle received therein to permit plug terminals of an electrical appliance to be inserted therein. The adapter bodies are kept open to form a V-shape by an elastic force.