PURPOSE: To increase magnetic flux and output torque by shortening average magnetic path length rotor and reducing a magnetic resistance.

CONSTITUTION: A rotor core body 10 having a plurality of salient poles 12a, 12b,... projected at the external circumference keeping interval is held by the supporting members 20, 20' with a supporting piece 22 extended from a supporting plate 21 engaged with a recessed portion 15 provided between the salient poles. A supporting axle 26 is provided on the supporting plate in the direction opposed to the supporting piece 22. The center of the rotor core body 10 is not provided with an axle which has a large magnetic resistance to prevent flow of magnetic flux. Therefore the magnetic flux flows linearly between the poles provided opposed with each other without branching and alternation.