The disclosed subject matter includes providing a surface light source device with high brightness that can emit light from both surfaces and an LCD unit having the same qualities. The surface light device can include a light guide having a light incoming surface, a reflecting sheet located adjacent the light guide, a transparent sheet having a light incoming surface located adjacent the reflecting sheet and a light source located toward both light incoming surfaces. Light emitted from the light source can be configured to enter into the light guide and the transparent sheet via the light incoming surfaces. The light can be efficiently emitted in both directions from the light guide and the transparent sheet using the reflecting sheet. Therefore, an LCD unit that includes an LCD located adjacent the light guide and a second display located adjacent the transparent sheet can illuminate displays with higher brightness.