The illumination device is provided with a plurality of light guide bodies, the bottom face of which is given light reflection/scattering treatment, light sources individually connected to the end portions of a plurality of the light guide bodies to radiate the bottom faces of a plurality of the light guide bodies, and a control unit for changing the intensity of light made incident from the light sources to a plurality of the light guide bodies. A plurality of the light guide bodies are laminated so as to be at least partially overlapped at the respective light emitting regions of the light guide bodies, and the control unit allows the intensity of light made incident from the light sources to the light guide bodies to change with the lapse of time.