The invention provides an illumination device for a display device, and a display device. The illumination device for a display device has light sources (17) arranged side by side and also has a light reflection plate (14) placed on the opposite side of the light emission side of the light sources (17). The light sources (17) are constructed such that their arrangement gaps on the inner side of the arrangement are narrower than those on the outer side. The light reflection plate (14) has mountain-shaped reflection sections (40) positioned between adjacent light sources (17). Each mountain-shaped reflection section (40) has two slopes (41, 42) each facing each of adjacent light sources (17) and extending in the longitudinal direction of the light sources (17). The two slopes (41, 42) are arranged such that more amount of light is reflected on the outer side, relative to the arrangement, of the center position (O) between two adjacent light sources (17) than on the inner side.