Abstract: A conventional projector headlamp has low efficiency because an amount of light is shaded almost half by a shutter for a low-beam light distribution. In addition, only a projection lens is seen in the installed condition, inviting old-fashioned designs disadvantageously. In a projector headlamp (1) of the invention, a vertical section passing through the center of a projection lens (5) includes a convex front surface and a flat rear surface (5a). A line connecting the upper end to the lower end on the rear surface (5a) is tilted to the vertical. Thus, the projection lens (5) has a prismatic action for directing the entire light downward. This is effective to reduce an amount of light to be shaded by a shutter (4) and provide improved brightness and novel designed appearances.