There is provided a surface light source device having a configuration where light sources are arranged on both of a pair of side surfaces of a light guide plate and allowed to independently form nonuniform light emission intensity distributions in which light emission intensity is lower and higher at places closer to and farther from each of the light sources. Light guide control sections controlling guiding of light from light sources are arranged on a reflection surface of a light guide plate. The light guide control section is configured of concave sections, and the concave sections include inclined surfaces facing the light source and inclined surfaces facing the light source, respectively, and the heights of the concave sections increase with increasing distance from the light source. A nonuniform light emission intensity distribution in which light emission intensity is lower and higher at places closer to and farther from the light source is formed by lighting of the light source. As the inclined angles of the inclined surfaces are larger than the inclined angles of the inclined surfaces, an influence of the light guide control section on light from the light source is reduced.