PURPOSE: To attain a high magnetic flux density, by providing shielding members on planes perpendicular to and parallel with the direction of the orientation of a shaped anisotropic magnet piece and using the shielding member on the parallel plane as a mangetic pole.

CONSTITUTION: Anisotropic magnets 5 are oriented in the S-N direction and surround a shielding member 6 made of a cold-rolled steel plate. Another shielding member 7 made of the same material is in contact with a plane perpendicular to the direction of the orientation of the magnets and is also in contact with the former shielding member 6. The magnets are nylon resin magnets containing powder of anisotropic ferrite. According to this constitution, little magnetic flux leaks from the faces parallel with the direction of the orientation because the direction of easy passage of magnetic lines of force is limited. Since the surfaces of the shielding member 6 and the magnets 5 are near each other, the modulus of permeance of a magnetic flux generation space is increased and a high magnetic flux density is attained.