To provide a respiration action of a lamp built in an outer mirror and an excellent water proofing effect.

Respiration holes 58, 31 and a grommet 8 are provided on a lamp 5 and a mirror housing 3. The inside of the lamp 5 is communicated with the outside of the mirror housing 3 via the grommet 8 and the respiration holes 58, 31. A cover 9 for covering the respiration hole 31 is provided on the mirror housing 3. The cover 9 is provided with a communicating hole 90 for communicating the external air with the inside of the cover 9. Since a respiration mechanism of the lamp 5 is thus provided, the inside of the lamp 5 does not become cloudy. Since the respiration hole 31 is covered by the cover 9, water does not directly splash on the respiration hole 31, or hardly splashes on it, and water can be prevented from intruding into the lamp 5.