A surface light source device includes: a plurality of LEDs emitting a light; a substrate having the plurality of LEDs mounted thereon; a light distribution control element arranged on the substrate, and distributing the light emitted from the plurality of LEDs; a reflection sheet reflecting a part of the light distributed by the light distribution control element to a display surface side of the surface light source device; a housing accommodating the plurality of LEDs, the substrate, the light distribution control element, and the reflection sheet; and a retaining member retaining the light distribution control element and the substrate under a state in which the retaining member is in contact with a surface of the light distribution control element that is opposite to a surface of the light distribution control element in contact with the substrate.