A backlight unit 12 includes LEDs 17, a light guide plate 19 including a light entry end surface 19b, a light output plate surface 19a, and an opposite plate surface 19c, a wavelength conversion sheet 20, and a reflection sheet 25. The light guide plate 18 includes a parallel plate surface 27 on a central portion of the opposite plate surface 19c and parallel with the light output plate surface 19a, and an inclined plate surface 28 on a part of the outer peripheral side portion and being inclined with respect to the light output plate surface 19a to be closer to the light output plate surface 19a as is closer to the outer peripheral end surface. The wavelength conversion sheet 20 overlaps the light output plate surface 19a and contains a phosphor that wavelength-converts the light from the LEDs 17. The reflection sheet 25 overlaps the opposite plate surface 19c and reflects light, and includes a parallel reflection portion 29 along the parallel plate surface 27, and an inclined reflection portion 30 along the inclined plate surface 28.