There is provided a movable shade which can move between a light shielding position and a light shielding moderating position, so that a single lamp can be used both for low beam and high beam. Then, the longitudinal length of the lamp is shortened so as to attempt to make the lamp compact in size by inserting a light source bulb into a reflector from a side of an optical axis Ax. As this occurs, the insertion and fixing of the light source bulb is implemented at a position which is apart downwardly from the optical axis, whereby the formation of a light source bulb inserting and fixing hole in optical axis sideways areas on a reflecting surface of the reflector is avoided which would otherwise have to occur.