To provide a motor which is made free of a resonance sound source and a vibration exciting force in rotation.

A heating device which has projection-shaped heat conduction parts 26, heated to a prescribed temperature by an internal heating means, at equal intervals along the outer peripheral surface by as many as a multiple (n) (n: integer larger than or equal to one) of the number of magnetizing poles, and a holding device which holds a magnetized permanent magnet, are arranged so that the heat conducting parts 26 are in contact with the heated surface 13 of the permanent magnet 11. The holding device 1 and the heating device are rotated synchronously to heat the heated surface of the permanent magnet at equal intervals as many times as a multiple (n) (n: integer larger than one) of the number of the magnetic poles, and thus an (n)-th order higher harmonic of magnetic flux density waveform generated on the magnetized surface of the permanent magnet is substantially removed.