A surface light-source device includes: a plurality of point light sources; a light-guide plate arranged for emitting from its emitting surface the light incident on one lateral side thereof from the point light sources; a lower case having a lateral side formed approximately in parallel to the incident surface of the light-guide plate; and a light-source substrate on which the plurality of point light sources are arranged at predetermined intervals, disposed on the light-guide plate side. The surface light-source device is includes a substrate holder that clamps the light-source substrate and the lateral side of the lower case by projections arranged on the substrate holder between adjacent two of the light sources.