As the annular translucent member, an annular lens formed from a
peripheral edge portion of a convex-meniscus lens is disposed between a
projection lens and a reflector along an outer peripheral edge of the
projection lens. Direct light from a light source toward a space beyond
the outer periphery of the projection lens is caused to illuminate
forward of the lamp by the annular lens, thereby effectively utilizing
light source luminous flux. In relation to the above, a shape of a back
surface of the annular lens is formed into a spherical surface having its
center at a luminescence center of the light source. Accordingly, direct
light from the light source can travel straight without being deflected
by a back surface of the annular lens, whereby a light deflection angle
on a front surface of the annular lens can be calculated easily and with
good accuracy.