A backlight unite 12 includes LEDs 17, an optical member 16, a positioning portion 23, and a rotation restricting portion 24. The optical member 16 includes at least a curved end surface 16C having a curved shape in a plan view included in a periphery of the optical member 16. The positioning portion 26 includes a positioning hole 25 that opens through a thickness direction of the optical member 16 and a positioning protrusion 26 that is inserted in the positioning hole 25 and is in contact with an inner wall of the positioning hole 25. The rotation restricting portion 24 includes an optical member recess 27 that is a portion of the periphery of the optical member 16 recessed along a circumferential direction and a contact portion 28 that is in contact with the optical member recess 27.