At a time of a heating high-load operation, a harmonic current is flown in an armature winding to induction-heat rare-earth magnets, thus reducing a residual magnetic flux density. Thereby, the number of rotations of a radial gap type motor is improved. The rare-earth magnets are provided near a cooling medium passage extending substantially in parallel with a flow line of a cooling medium, so that the cooling medium recovers heat of the heated rare-earth magnets. At a time of a cooling high-load operation, a greater number of rotations are obtained with respect to the same torque command value, by a field weakening control by means of a current-phase advance.