To provide a simple and easy mounting of a receptacle to a switchboard or a distribution board.

Engaging parts 2b, 2b to be slidingly engaged to a mounting.rail 3 attached and fixed to a switchboard or a distribution board and the like are provided projecting toward a bottom surface part, and a receptacle support base 2 that projection 2a to be push-in fitted in a mounting hole 11a provided on a main body 11 of a receptacle 1 is provided projecting upward on a top surface part. The main body 11 is assembled and fixed on the top surface part of the receptacle support base 2 by push-in fitting the projection 2a in the mounting hole 11a, a cover part 12 is mounted after connecting an electric wire to a connecting terminal of the main body 11, and the engaging part 2b is slidingly engaged to a flange 3c of the mounting rail 3. Thereby, a receptacle generally available on the market is mounted on the mounting rail 3 of the switchboard or the distribution board and so on through the receptacle support base 2.