A cylindrical bearing box 2 is integrally provided at the axial center of an annular disk 1 on which a flange 1a is formed. A shaft 3 is attached to a pair of bearings 2a, 2b engaged with the bearing box 2. A rotary disk 4 attached the shaft 3 on a side opposite to the drive side is molded integrally with a conductor 5a of a rotor 5 arranged outside of the bearing box 2 in the radial direction. A stator 6 arranged outside of the rotor 5 through a magnetic clearance is attached to the stationary side of the rotary electric machine. A synthetic resin member 7, the electric insulating property and heat conductivity of which are high, is molded in the overall periphery of the stator 6 including the winding 6a and the iron core 6b. An end face of the synthetic resin member 7 on the drive side is closely contacted with the annular disk and attached by a screw 1b. Blades 4a are provided on an outer end face of the rotary disk 4 and enclosed by a fan cover 4b. A shaft seal device 8 is provided in a gap formed between a small diameter end face portion 7a of the synthetic resin member 7 on a side opposite to the drive side and the rotary disk 4.