PURPOSE: To reduce the power consumption in a coil and to obtain high sensitivity of the device when the coil is excited and an armature is rotated, by aiding the rotation of the armature by the magnetic fluxes of two permanent magnets.

CONSTITUTION: A stator core 1 is constituted by a base part 1a and four finger parts 1bW1e in an H shaped. The coil 2 is wound around said base part 1a. Meanwhile a yoke 3 is also constituted by a base part 3a and four finger parts 3bW3e. Said core 1 and yoke 3 are arranged in parallel with a specified gap being provided. The armature 4 is arranged in the gap. The two parallel permanent magnets 5 and 6 are connected by a non-magnetic body 7 in the armature. The magnets 5 and 6 are so arranged that the north poles and the south poles are positioned in the opposite directions to each other. They are teetered with an axis 8 as a center. When the coil 2 is excited and the armature is rotated, while the rotation is assisted by the magnetic fluxes of the magnets 5 and 6.