A surface light-source device of a display unit comprises a light source, light guide plates and reflector sheets. The light guide plate has an emission surface for emitting the light of the light source as planar light. The reflector sheet reflects the light of the light source, which has entered the light guide plate, toward the emission surface. At rear surfaces of the light guide plates, grooves and incline surfaces are formed. The grooves contain the light source. The incline surfaces have a V-shaped section and reflect the light of the light source, which has entered the light guide plate, toward the emission surface. The light guide plates are disposed such that the rear surfaces thereof closely confront each other so as to interpose the light source between the grooves.