To cool the stator of a small-sized motor by generating an air current in the axial direction while the rotor of the motor rotates by providing spaces extended in the axial direction and a plurality of blades in a hub section which couples the permanent magnets of the rotor with the shaft of the rotor.

In the rotor 7 of a PM type motor which is faced to the internal peripheral surface of the stator of the motor with a gap in between, spaces A and B extended in the axial direction and a plurality of blades 9 are provided in a hub section which couples the permanent magnets 8 of the rotor 7 with the shaft 5 of the rotor 7. The blades 9 are integrally formed with a boss section 19 by using the same member as that of the magnets 8 and the blades 9 are spirally formed in the axial direction so that the axial spaces A and B can be formed between each blade 9. Consequently, an air current is generated by the blades 9 in the axial direction through the rotor 7 when the rotor 7 rotates and the stator can be cooled effectively. Therefore, a small-size motor which has a simple constitution and the temperature of which does not rise much can be obtained.