The disclosed subject matter includes a projector headlight using a plurality of optical units for a low beam with a high visible/visual quality. Each of the optical units can include a plurality of LED devices and a projector lens. The projector lens can include a light-emitting surface including a reflex function and a reflex surface including a light incoming surface that is located on the opposite side of the light-emitting surface. The LED devices can be located adjacent the light incoming surface, and the optical units can be located so that angles between optical axes of adjacent optical units can become substantially a same angle. Thus, the projector headlight can form various favorable light distribution patterns by changing curvature factors of the light-emitting surface and the reflex surface of the projector lens in each of the optical units and by changing the angles between the optical axes of the adjacent optical units.