There is provided a surface light source device capable of making appearance of a boundary between partial lighting areas more natural than related art. In each of unit light-source sections 10 capable of mutually independent lighting, uneven light-emission intensity distributions that are mutually independent are to be formed within a light emission surface. Thus, in the light emission surface of each of the unit light-source sections 10, an arbitrary light-emission intensity distribution is able to be formed. Therefore, by adjusting a light-emission intensity distribution of each of the unit light-source sections 10, the appearance in the boundary between the partial lighting areas becomes more natural than related art.