A backlight device 12 includes LEDs 15, a light guide plate 17 having a light entering edge surface 17a opposite the LEDs 15 and having plate surfaces one of which is alight exit plate surface 17b, and a light collecting portion 22 including unit light collecting portions 22a that extend in a normal direction of the light entering edge surface 17a on the light exit plate surface 17b and are arranged in a perpendicular direction perpendicular to the normal direction. The light guide plate 17 includes an opposite edge portion 23 that is opposite from an end portion thereof having the light entering edge surface 17a, the opposite edge portion 23 has an edge surface a part of which is a curved edge surface 24 having a curved planar shape and the opposite edge portion 23 has the light exit plate surface 17b a part of which is a light collecting portion non-forming section 25 on which no light collecting portion 22 is formed.