PURPOSE: To obtain a polar electromagnet apparatus used as a highly sensitive type electromagnetic relay by making the return motion of an armature only by the magnetic circuit of an electromagnet apparatus.

CONSTITUTION: When a coil 5A is not excited, between yokes 2 and 3 is magnetized by a permanent magnet 1 in polarity as shown in Drawing (A). Consequently, an armature 5B is absorbed between the free ends 2A and 3A of yokes 2 and 3 and a magnetic circuit B1 shown by a dotted line is formed. If the coil 5A is excited, a repulsive force is generated between both the free ends 2A, 3A and the armature 5B and the armature 5B is moved in parallel as shown in Drawing (B) and is absorbed to a yoke 4 as shown in Drawing (C). In other words, a magnetic circuit B2 as shown by a dotted line is formed by the magnetic force of an electromagnet 5. If the excitation of the coil 5A is ceased, both the free ends 4A and 4B of the yoke 4 are demagnetized and the armature 5B is returned to a position shown in Drawing (A).