An illumination device is provided on a backside of a display panel so as to irradiate a display panel with light, the illumination device including a plurality of rod-like light sources arranged in a planar configuration such that they do not cross each other, and columnar members being respectively provided adjacent to the rod-like light sources, each columnar member including a light incidence plane through which light emitted from a longitudinal direction of the rod-like light sources enters, a first light exit plane arranged to emit the incoming light from the light incidence plane toward the display panel, and a first light reflecting plane arranged to reflect the incoming light from the light incidence plane to the light exit plane. Therefore, with the illumination device applied as a direct backlight, it is possible to reduce luminance unevenness in both a front direction and oblique directions sufficiently, so as to reduce the luminance unevenness of the backlight sufficiently, as a whole.