In a liquid-crystal display device, an optical path control layer is provided at least on an outer side of the back side substrate, and has a plurality of optical path changing slopes inclined at an inclination angle of from 35 to 48 degrees with respect to a reference plane of the back side substrate. The optical path control layer has a refractive index higher than that of a low-refractive-index transparent layer provided in the back side substrate. Another low-refractive-index transparent layer lower in refractive index than the transparent substrate may be provided in a visual side substrate. Light sources may be disposed on at least two side surfaces of the liquid-crystal display panel. Light sources may be disposed on side surfaces of the back side substrate and the visual side substrate and at least on side surfaces of the liquid-crystal display panel which are different from each other. Another optical path control layer may be provided also on an outer side of the visual side substrate.