A light guide plate has a hologram pattern on a light exit surface. The hologram pattern anisotropically diffuses light in the direction parallel with a light incident surface of the light guide plate. On a back surface of the light guide plate are formed mirror-polished prism structures extending parallel with the light incident surface. A downward-pointing prism sheet with a given prism apex angle is placed on the light exit surface of the light guide plate. The use of the downward-pointing prism sheet together with the light guide plate having the anisotropic diffusion hologram pattern integrally formed thereon produces a liquid crystal display device with enhanced luminance properties.