Abstract: A surface emission light source device includes a light source, a light guide plate, and a reflecting plate. The light guide guides light from the light source and causes the light to emerge from its front surface. The reflecting plate has an irregular-reflection surface formed of irregular corrugations, and is disposed on a lower surface of the light guide plate. The reflecting plate diffuses and reflects the light guided through the light guide plate with the irregular-reflection surface, and causes the diffused/reflected light to emerge from the front surface of the light guide plate. The light guide plate and the reflecting plate are integrally formed by molding, to bond the irregular-reflection surface to the lower surface of the light guide.