Motor apparatus having rotational position detector

The motor apparatus 1 is provided with a yoke housing 4, a gear housing 41and a brush holder 7. A receiving portion 51a of the gear housing 41 receives the worm wheel 43, etc. therein. The brush holder 7 is interposed between the yoke housing 4 and the gear housing 41. The worm wheel 43 is provided with a switching plate 54 on one face thereof, which is in slide contact with contact members 31 - 33. The gear housing 41 is provided with a housing body 51 and a cover 52. In the housing body 51 is formed a communication hole 51d to communicate an internal spaces of the receiving portion 51 a and a yoke housing 4. The contact members 31 - 33 are disposed on the brush holder 7 and on the bottom portion side of the receiving portion 51 a with respect to the worm wheel 43 so as to extend through the communication hole 51 d into the gear housing 41.