In the rear of a collimator lens there is disposed a reflector having a bulb serving as a light source, and a shade is interposed between the collimator lens and bulb. The reflector is mounted by means of a guide engagement mechanism, which is arranged such that guide pins provided in the front edge portion of the reflector are pivotally and slidably engaged with a plurality of guide grooves formed in a guide plate fixed on the side of the collimator to thereby be able to deflect an optical axis. The guide engagement mechanism controls or displaces the reflector by use of a control motor. The shade is fixedly secured on the side of the collimator lens.