To easily perform slip-off prevention of a plug and a receptacle without twisting a power cable and to prevent the outside diameter from being increased without requiring clamping torque management.

In this connector, an annular groove 5 is provided on the outer periphery of a plug 2, and clamp inserting parts 15 are provided on a receptacle 11. When a clamp 20 is inserted into the clamp inserting parts 15 after the plug 2 and the receptacle 11 are fitted to each other, the clamp 20 is dropped in a groove 5 on the outer periphery of the plug 2, and the plug 2 and the receptacle 11 can not be drawn out. Therefore, slipoff prevention of the plug and the receptacle can be easily performed.