An illumination device is capable of receiving a signal from a display control device for displaying an image on a display screen. The illumination device includes a reception portion and a lighting portion. The reception portion receives a control signal from the display control device. The lighting portion emits a plurality of rays of visible light each having an elongated cross section in accordance with the control signal received by the reception portion. For example, the rays of visible light are shed on a wall surface behind the display screen.