In a headlamp assembly, a reflector unit includes a bearing surface for supporting a lighting control circuit. The lighting control circuit is mounted to the backside of the reflector unit across a holder, and directly connected to a discharge bulb. The reflector unit further includes a mounting portion to which a lampshade unit is mounted. In the reflector unit, the backside of the mounting portion is offset from the bearing surface in both of the axial direction and the radial direction. That is, the lampshade unit and the holder are fixed to the reflector unit so as to be distanced from each other. Thus the holder is thermally disconnected from the lampshade unit, and thereby the heat transfer from the lampshade unit to the lighting control circuit is reduced.