PURPOSE: To prevent chattering and improve accuracy in positional detection in a wiper drive motor with an automatic home-positioning mechanism.

CONSTITUTION: A wiper drive motor 10 with an automatic home-positioning wiper mechanism has a cover 18 with a cylindrical recessed part 59 formed at a center of a rotation axis of a contact plate 24, while the contact plate 24 has a cylindrical projected part 26 at the center of the rotational axis thereof. The cylindrical projected part 26 has a plurality of projected parts 23 on the outer face. Then, the cylindrical part 26 is inserted in the recessed part 59 of the cover 18 so that the projected parts 23 are slid on the inner circumferential face of the recessed part 59, and the contact plate 24 is supported in a radial direction.