An upper portion region and a lower portion region at a front side surface of a projector lens are constituted as up and down direction diverging portions provided with a plurality of lens elements extended substantially in a horizontal direction by a vertical sectional shape formed in a recessed and projected shape relative to a reference face of the front side surface. After diverging light emitted from the upper portion region and the lower portion region to a front side in an up and down direction, a diverging degree thereof is made to be able to be controlled accurately to thereby pertinently shade off the cutoff line. A spectroscopic color appearing at an upper vicinity of the cutoff line owing to a spectroscopic light phenomenon brought about when light reflected from a reflector transmits through the projector lens is made to be inconspicuous.