To provide a technology in which reduction of an outgoing light luminance can be prevented and the outgoing light luminance can be homoge nized effectively when an LED is arranged at the rear face side of a light guide plate and the light of the LED is made to be a surface-formed illuminating light via the light guide plate.

Among the light from the LED 4, the light directly outgoing from an outgoing face 5 without being reflected at an inclined face 12 of the light guide plate 2 is reflected at a light reflecting part 10b of a light shielding member 10 to be returned back to the inside of the light guide plate 2, and effectively utilized later as the illuminating light. Further, a highly luminous light component to apt to become an anomalous light emission is absorbed at a light absorbing part 10a of the light shielding member 10. As a result, as for an image display device 1, homogenization of the luminance of outgoing light can be aimed at without inviting the reduction of the luminance.