To improve an electric contact reliability.

A power-off device 1 consists of a housing 4, a rotary switch 2, and a torsion coil spring 3. A power supply side terminal 10 and a load side terminal 11 are stored in predetermined positions of the housing 4, and a conductive element 7 is equipped with the rotary switch 2. The torsion coil spring 3 reaches its maximum flexure just before the conductive element 7, previously contacting the load side terminal 11, contacts the power supply side terminal 10 by turning the rotary switch 2. This increases turning speed of the rotary switch 2 just before the power supply side terminal 10 and the load side terminal 11 short-circuit, and an arc discharge is easily extinguished.