The IPM motor (hereinafter called motor) 1 operates as a drive source of a hybrid vehicle or an electric vehicle, for example, and includes a stator 2 having a coil 7 wound therearound, and a rotor 3 rotatably disposed inside of the stator 2.

The stator 2 includes an annular iron core 6 including magnetic steel sheets or a nanocrystal soft magnetic material described later, and a plurality of coils 7 wound around the iron core 6. The coils 7 are disposed in the form of concentrated winding or distributed winding and on the inner periphery of the stator 2 at regular intervals. Current flowing through the coils 7 generates rotating magnetic field to rotate the rotor 3.

The rotor 3 includes a rotor core 30, a rotary shaft 4 inserted into a shaft hole 31 at a center of the rotor core 30, and a plurality of magnets 5 (5L, 5M, 5R) embedded in a plurality of through-holes 32A in the rotor core 30. The rotary shaft 4 is made of metal. The rotary shaft 4 is inserted into the shaft hole 31 of the rotor core 30, and then is fixed to the rotor core 30 by caulking, for example.