The planar light source device

In the planar light source device using a point light source, to improve heat dissipation, unevenness in luminance between the inhibition of point light sources. Planar light source device includes: a plurality of point light sources (1); a light guide plate (4), at least from one side of incident light from the point light source (1) is emitted from the emission surface; the lower case (8) having a guide side surface of the light plate (4) of the incident surface (a) is formed substantially in parallel; light source substrate (2), a plurality of point light sources (1) arranged at a predetermined interval, arranged in the (a) side of the incident surface of the light guide plate; wherein the resin comprising a frame (3), sandwiched between the light source substrate (2) with the side portion of the lower case (8), a gap in the point light source portion (1) corresponding to the portion, and supports the light guide plate (4 ) end portion of the exit surface (B) is.