To make illumination uniformity more highly adjustable than in any conventional method in arranging a plurality of light sources onto the light incident plane of a light guide plate without using another component such as a lighting curtain even when those light sources are not uniformly arranged or are uniformly arranged.

An auxiliary light incident part 110 provided with partitioned incident planes 111, 112 assigned to each of the light sources 20S1, 20S2 respectively is formed on the light incident plane 11 of the light guide plate 10. The respective light sources 20S1, 20S2 are arranged in such a way that their respective optical axes C1, C2 are inclined so as to bisect an area of the light incident plane (an illumination range) of the light guide plate 10. At the same time, the respective partitioned incident planes 111, 112 are formed so as to perpendicularly intersect the respective optical axes C1, C2 of the light sources 20S1, 20S2.