PURPOSE: To suppress unnecessary high frequency components and reduce vibration and noise by laminating unit plates constituting a stator, sliding them in the same direction in order with the rotary shaft of a rotor as the central axis.

CONSTITUTION: A stator is equipped with several sets of fixed magnetic poles 21, wherein unit plates 22 are laminated into an iron core and windings are wound thereon. And these are laminated while rotating them 1° at a time centering around the rotary shaft, from one side in the axial direction of the rotary shaft 12, and are laminated so that the shape from the side of the fixed magnetic pole 21 may be trapezoid. And individual unit plates 22, which constitute a stator by being laminated, are laminated, being slid in the same direction in order with the rotary shaft of the rotor as a central axis. Accordingly, the change of the facing area between the rotary magnetic pole 11 and the fixed magnetic pole 21 by the rotor rotating becomes gentle.