A backlight device includes LEDs, a unit body holding the LEDs, a light guide plate having a light entrance edge surface and a light exit plate surface, and a chassis. The light entrance edge surface is a part of outer peripheral edge surfaces of the light guide plate and extends in a peripheral direction and light from the LEDs enters through the light entrance edge surface. The light exit plate surface is one of plate surfaces of the light guide plate and light exits through the light exit plate surface. The LEDs and the light guide plate are arranged in the chassis and the chassis has a fitting hole that is open in a direction crossing an extending direction of the light entrance edge surface such that the LEDs are inserted in and removed from the fitting hole according to mounting and detaching of the unit body.