PURPOSE: To prevent a part made of a conductive magnetic material from blowing off at large current breaking time by fixing a part made of a conductive magnetic material in at least both sides of a movable contactor at the positions more forward than the contact point.

CONSTITUTION: Being put at the positions more forward than a contact point 4 of a movable contactor 2, conductive parts 12 made of a magnetic material are fixed in both sides of the movable contactor 2 from both sides. Since the parts 12 are set more forward than the contact point of the movable contactor 2 and fixed in its both sides, there is no part of a conductive part 10 whose cross section area becomes small. Consequently, there is no possibility that the parts 12 are blown off and thus high reliability is obtained.