An illumination device for emitting light includes a light incident body having a first end portion that has a light incident surface on which light from a light source is incident, a second end portion, and an outer oval-shaped surface portion interconnection the first and second end portions. A light guide plate is optically coupled to the second end portion of the light incident body and has a light emitting surface through which light that propagates through the light incident body is emitted. The light guide plate and the light incident body are integrally formed and may comprise a one-piece body. A display device utilizes the illumination device for illuminating a display element of the non-self light emitting type.