PURPOSE: To improve the reliability and durability of a motor by a method wherein the contamination and/or damage of the circuit substrate, sensor and the like of a motor are eliminated by a simple and inexpensive structure while a stress, generated in the circuit substrate when a connector is inserted, is also eliminated.

CONSTITUTION: An inflated part 44 for covering a circuit substrate 35 for connecting motor terminals 28, 29 and a projection 45 for supporting the back surface of a connector 41 fixed to the circuit substrate 35 are formed on one part of a dust-proofing cover 36 covering a motor.