A surface light source device, a light guide body and a manufacturing method thereof used therefor

A light incident end face, the light emitting surface (242), a plate-shaped light guide comprising a rear surface (243) located on the opposite side of the light emitting surface (242) (24). At least one of the light emitting surface (242) and a rear surface (243) is at least in some regions, the foamed surface layer (244) is formed, foamed surface layer (244) and the light emitting surface includes a bubble (242) or section including the direction of the normal of the rear surface (243) is formed into a concave shape. Light guide (24) is performing the infrared laser etching to at least part of a region of at least one main surface of the plate-like light guide material consisting prepared acrylic resin plate by a continuous steel plate method in, it is produced by forming the foamed surface layer (244).