PURPOSE: To check a sense of visual incompatibility at time of a beam switchover by constituting a main beam with an incandescent lamp and a dimmer beam with a discharge lamp, respectively, and when the main beam is lighted, making the dimmer beam go on simultaneously.

CONSTITUTION: Both right and left headlights 1a, 1b consist of each of incandescent lamps (inclusive of halogen lamps) 3a, 3b and discharge lamps 5a, 5b, while these incandescent lamps 3a, 3b compose a main beam (Hi beam) and the discharge lamps 5a, 5b for a dimmer beam (Lo beam), respectively. These discharge lamps are controlled by respective discharge lamp control circuits 11, 13, and the incandescent lamps 3a, 3b and the discharge lamps 5a, 5b are all lighted simultaneously by a main lighting switch 25, and discharge lighting of the these discharge lamps is made so as to be performed by operation of a dimmer lighting switch 27. Moreover, at time of main beam lighting, a light value of the dimmer beam is constituted to be reduced to some extent, through which a specified coloring pattern and the light value are satisfied without entailing any damage to a white color.