PURPOSE: To eliminate the loss of magnetic flux by making the magnetic flux of a coil reach magnetic gaps without passing through a permanent magnet.

CONSTITUTION: When magnetic flux shown by the broken line is generated within a yoke 1 by exciting a coil 4, the magnetic flux polarization arises in magnetic gaps 10 at both sides of an armature 12 because a permanent magnet 7 produces its magnetic flux in the direction shown by the solid line. This polarization causes the free end part of the armature 12 to rotate in the direction indicated by the arrow and more a movable frame 13 engaging the armature in the same direction, thereby making contact between a fixed contact 22 and a movable contact 20 while breaking contact between a fixed contact 21 and a movable contact 19. At this time the magnetic flux by the coil 4 does not pass through the inside of the parmanent magnet 7, therefore, all the magnetic flux acts upon the magnetic gaps 10, reducing the loss of the magnetic flux and improving the electromagnet's sensitivity and responsiveness.