An apparatus includes a two-sided prism sheet, and an optical path conversion unit with linear prisms. Each apex angle of the prisms increases the closer the linear prism is formed to the center in the light guide direction, and when a pair of inclined surfaces of each of the prisms has a first inclined surface and a second inclined surface, an inclination angle of the second inclined surface is larger than the one of the first inclined surface. Among the prisms, inclination angles e1 and e2 of a pair of inclined surfaces of a linear prism formed closest to the center and an inclination angle c of the first inclined surface and an inclination angle d of the second inclined surface of a linear prism formed closest to the side end surfaces at which the light sources are disposed satisfy a relationship 2×c