A flexible substrate mounting the light sources thereon realizes a shape which can eliminate a largely projecting portion and a liquid crystal display device which uses such a flexible substrate is obtained. A strip-like portion is formed by providing an elongated cut in a flexible substrate and light sources are mounted on the strip-like portion. Due to such a constitution, the strip-like portion mounting the light sources 5 thereon has a shape which is substantially arranged parallel to the shape of the main portion 8 which occupies a most portion of the flexible substrate land hence, it is possible to eliminate a largely projecting portion. Then, the light sources 5 are arranged such that the strip-like portion is folded back at least once such that light from the light sources is incident on a light guide body 4.