To enhance radial restoring force with simple structure and prevent the generation of demagnetization with the lapse of time by forming the overlapped structure of a plurality of ring-like permanent magnets on both rotating side and fixed side, and piling the radially magnetized permanent magnets in such a way that the magnetized directions are reverse.

A pluraility of ring-like permanent magnets 26, 26, 26 are formed in an axially overlapped state on the fixed side. The respective ring-like permanent magnets are radially magnetized in the magnetic pole mangetizing direction of N-poles and S-poles. Ring-like permanent magnets 25, 25, 25 on the rotating side are also magnetized radially in the magnetic pole magnetizing direction of N-poles and Spoles. The inner peripheral surface of the fixed side permanent magnet and the outer peripheral surface of the rotating side permanent magnet are axially aligned so as to face each other with a void A. The facing magnetic poles in the A are therefore like-poles, so that magnetic repulsive force works, and a rotor receives radial force so as to be supported in a levitated state, thus constituting a radial magnetic bearing.