PURPOSE: To maintain the prescribed contact pressure without changing the contact pressure to the coil of a contactor, to provide an elastic member as small as possible, and to improve the reliability of the rotary structure part of the contactor.

CONSTITUTION: The title inductance variable coil is provided with a tortion coil spring 5 with which a contactor 1 is brought into contact with the inner surface of a coil 4, the second arm 9 which is matched to the superpositional moment of the cotactor 1 and the like with the tortion coil spring 5 as the center point and the first balancer 3, and the effect of the moment of change in contact position of the first contactor 1 is not given to the tortion coil spring 5.