PURPOSE: To obtain illumination having no unevenness in intensity of illumination, by reflecting rays of light from light sources by means of a spherical reflecting surface and plane reflecting surface and leading the rays of light in a prescribed direction.

CONSTITUTION: When rays of light from tubular light sources 4 and 5 are reflected in a wide angle by means of a spherical reflecting surface 2, the reflecting surface 2 receives the rays of light from the light sources 4 and 5 and rays of light which are totally reflected by a transparent plate 6. Therefore, it is considered that light source centers exist at the centers O1 and O2 of the light sources 4 and 5 and mirror images 4' and 5' and the rays of light which are regarded as those emitted from the center O1 in the directions A1 and A2 are reflected in the directions Am and An by the spherical reflecting surface 2. Moreover, rays of light which are directly projected on a plane reflecting surface 3 or those projected on the surface 3 after they are reflected by the surface 2 exist against the rays of light which are directly reflected toward the plate 6 from the surface 2, but those rays of light also advance toward the transparent plate 6 after they are reflected by the spherical reflecting surface 2 as shown by the light routes B1→Bm and B2→Bn. Therefore, illumination of uniform intensity of illumination can be obtained.