To facilitate the change between a circuit continuity state and a circuit breaking state and discharge a capacitor or the like in a load part when being changed from the circuit continuity state to the circuit breaking state.

A moving plug 3 having a current carrying part 41 is installed in a device body 2 so as to be linearly movable between a circuit opening position and a circuit closing position, and an earth side terminal 11, a load side terminal 12, and a power source side terminal 13 are installed by shifting the arrangement of them so that the earth side terminal 11 and the load side terminal 12 come in contact with the current carrying part 41 but the power source side terminal 13 does not come in contact with the current carrying part 41 in the circuit opening position of the moving plug 3, and the load side terminal 12 and the power source side terminal 13 come in contact with the current carrying part 41 but the earth side terminal 11 does not come in contact with the current carrying part 41 in the circuit closing position of the moving plug 3.