To change the light distribution characteristic to the width direction by switching a 2nd reflecting plane and a 3rd reflecting plane, in addition to the change of the light distribution characteristic of the light direction mainly in vertical direction by conventional filament switching.

In this illumination light 1, a light source 3a is placed at a 1st focal point F1 in the part of a 1st reflecting plane of paraboloidal system, a concave part is formed by providing a 2nd reflecting plane 5 of elliptical plane system with a 2nd focal point F2 in horizontal direction, and in this concave part, a 3rd reflecting plane 7 of paraboloidal system that can be inserted and removed as desired is provided, the 3rd reflecting plane 7 covers the 2nd reflecting plane 5 when it is inserted, and the light distribution characteristic continuous horizontally to the light distribution characteristic of the 1st reflecting plane is formed by the reflected light from the 2nd reflection plane 5 and a 2nd lens 6 when it is removed. Thus, the change of the light distribution characteristic to the width direction by the 2nd reflection plane and the 3rd reflection plane become possible in addition, to the change of the light distribution characteristic by conventional filament switching.