A light guide plate has a light incident surface arranged facing a plurality of point light sources arrayed in a line, a light exit surface orthogonal to the light incident surface, and two side surfaces orthogonal to the light incident surface and the light exit surface. Light from the plurality of point light sources introduced from the light incident surface is diffused by a diffusion unit arranged on the light exit surface or a surface facing the light exit surface. The light diffused by the diffusion unit is exited from the light exit surface. A distance between a point light source positioned at an end of the plurality of point light sources and the light incident surface is different from a distance between a point light source not positioned at the end of the plurality of point light sources and the light incident surface.