In a lighting device 12 according to the present invention, a first board 20a and a second board 20b on which a plurality of light sources 17 are mounted are arranged in a first board arrangement area 30a and a second board arrangement area 30b of a chassis 14, respectively, in respective predetermined orientations. The first board 20a includes a first board-side interlock portion 31a interlocked with a first chassis-side interlock portion 32a provided in the first board arrangement area 30a, and the second board 20b includes a second board-side interlock portion 31b interlocked with a second chassis-side interlock portion 32b provided in the second board arrangement area 30b. In arranging the first board 20a in the second board arrangement area 30b, the first board-side interlock portion 31a is not interlocked with the second chassis-side interlock portion 32b.