A backlight unit 12 includes a light guide plate 18, an LED 16, an LED board 17, a light exit portion 31, a board mounting portion 36, a clip 23 and a plate spring 47. The light guide plate 18 and the LED 16 extend in the front-to-rear direction. The rear part of the light guide plate 18 is fixed to the LED board 17 with a front part of the light guide plate 18 separating from the LED board 17. The light exit portion 31 is provided at a front part of the light guide plate 18. The light exit portion 31 has a light exit surface 36 from which light from the LED 16 exits and travel toward an optical member 15. The board-mounting portion 30 is provided at a rear part of the light guide plate 18 and mounted to the LED board 17. The clip 23 fixes the board-mounting portion 30 to the LED board 17. The plate spring 47 pushes a rear part of the board-mounting portion 30 located more to the rear than the clip 23 such that the rear part separates from the LED board 17.