Provided is an illumination device wherein, even when a light emitting portion having a shape elongated in one direction is viewed from any position in the circumferential direction, the contrast of light introduced from the light emitting portion can be suppressed. The illumination device has a power source unit for converting electric power supplied from the outside into a predetermined driving electric power; a light source unit which is connected to the light source unit and emits light using the driving electric power; a light guide unit with which a light guide piece for guiding the light of the light source unit from an input surface to an output surface is integrally formed; and housing units which are paired to contain the light source unit.
