A backlight unit includes an LED, a light guide plate, a light collecting portion, an opposite end portion, and a total reflection regulator. The light guide plate includes a light entering end surface opposed to the LED and a light exiting surface that is one of plate surfaces. The light collecting portion includes light collecting pieces extending on the light exiting surface in a normal direction to the light entering end surface and arrayed in an orthogonal direction perpendicular to the normal direction. The opposite end portion is on an opposite side from the light entering end surface. A section of the opposite end portion includes a curved end surface. The total reflection regulator is disposed on at least a portion of the curved end surface and configured to regulate the amount of light in the opposite end portion to be totally reflected by the curved end surface.