Abstract: Disclosed herein is a vehicular headlamp which comprises a lamp housing having a front portion opened; a lens covering the opening of the front portion; a lamp bulb installed in the lamp housing for generating light when electrically energized; a light reflector installed in the lamp housing for reflecting the light from the lamp bulb toward the lens; an angular position adjustment mechanism for adjusting an angular position of the light reflector relative to the lamp housing; a spirit level fixed to an outer surface of the light reflector to move therewith; and a window structure defined by either one of the lens or the lamp housing, through which the level is viewed from the outside of the headlamp.