A backlight unit includes side emitting-type LEDs, a light guide plate, and an LED board. The light guide plate includes a light entering end surface, a light exiting plate surface, and an opposite plate surface. The LED board includes a plate surface attached to an edge of the opposite plate surface of the light guide plate. A gap is present between light emitting surfaces of the LEDs and the light entering end surface of the light guide plate. Each LED includes a light emitting surface having a dimension in the thickness direction of the light guide plate smaller than a dimension of the light entering end surface in the thickness direction. Each LED is disposed such that the center of the light emitting surface is opposed to the center of the light entering end surface.