A lamp unit including mirror member 18 having an upward reflecting surface 18a, which reflects part of reflected light from a reflector 16 upward and is disposed between the reflector 16 and a projection lens 12. The mirror member 18 can be moved in the direction of an optical axis Ax and can take a reference position, where the front end edge 18a1 of the upward reflecting surface 18a is located at the rear focal point F of the projection lens 12, and a front movement position, which is located forward a predetermined distance from the reference position. When the mirror member is moved to the front movement position, part of the reflected light from the reflector 16 passes through a space behind the mirror member 18 so as to be incident on the lower region of the projection lens 12.