To secure excellent rotating properties and heat dissipation properties for a lamp unit, while alleviating risks of dust, moisture or the like entering a lamp room.

A cylindrical member 21 and projection lens 22, which form a light path of light irradiated from LEDs 19, and a lamp unit 17 consisting of a thermally conductive heat transmission part 24 are housed in the lamp room 14 structured of an outer lens 13 made of a transparent resin mold product fitted to a front opening 121 of the headlight 11. The lamp unit 17 has a function of turning in a horizontal direction by a right-and-left driving device 25 and are integrally coupled with the heat transmission part 24 so that a center point of a circular heat sink 261 be on a turning axis of the driving device 25. An opening 125 is provided on a top face 124 of the headlight 11, which is on the turning axis, to have the circular heat sink 261 exposed from the opening 125 outside the headlight 11.