Abstract: The illumination device has a simple structure and a small size, can obtain a sufficient illumination light amount, and can improve illumination ability, with high reliability and high performance at low costs. A kaleidoscope is arranged such that its center axis substantially corresponds to the optical axis of a light bulb. The kaleidoscope includes a diffusive reflection surface in its rear side, and a laser beam is irradiated on the diffusive reflection surface from the opening side of the kaleidoscope, so that reflection light from the diffusive reflection surface is used as an illumination light source.