PURPOSE: To improve reliability of a headlamp, to get its compactness and lightness, and to suppress decrease of the quantity of the light in a four lamp type headlamp which has a main beam and a dimmer beam in one body by constituting the headlamp so that any one of the main beam and the dimmer beam is an incandescent lamp and another is a discharge lamp.

CONSTITUTION: A four lamp type headlamp system is constituted so that two lamps, for example, a halogen lamp 1 as an incandescent lamp for a main beam and a discharge lamp 3 for a dimmer beam, make a pair. In this case, the halogen lamp 1 is controlled by means of a halogen lamp switching relay 5 as a second switch for performing ON-OFF operation of a power supply. In addition, the halogen lamp 1 is switched on in the case of ON of a beam change-over switch 25, and the discharge lamp 3 is switched on by discharge in the case of OFF of the switch 25. In other words, the beam change-over switch 25 constitutes a first switch for switching on the halogen lamp 1 by feeding. Furthermore, a control means is constituted for controlling ON-OFF of the halogen lamp switching relay 5 by means of a halogen lamp switching-on relay control transistor 29 of a discharge lamp control circuit 15 and a discharge control circuit 19 and the like.