A light guide plate 122 is shaped like a wedge whose thickness gradually decreases from the left end in the figure to the right end, and a light guide plate 142 is shaped like a wedge whose thickness gradually decreases from the right end in the figure to the left end. Since the wedges of the light guide plates 122 and 142 are arranged in a staggered manner, the thickness of the entire liquid crystal display device 100 can be reduced.