In a direct type point light source backlight using point light sources, a light diffuser is provided that can achieve coexistence of superior luminance, luminance uniformity (front and oblique views), and a color unevenness characteristic even with a desired backlight thickness and a few number of point light sources without using a number of optical films together.Specifically, provided is a light diffuser for point light sources, the light diffuser having a plurality of convex portions formed on a surface thereof, wherein the convex portion has a substantially triangular pyramid shape whose bottom surface is a triangle, and an inclined angle θ with respect to a bottom surface of a side surface of the substantially triangular pyramid shape and a refractive index A of a material forming the convex portion satisfy the following equations (1) and (2). θ≧−40A°+115.2°  (1) θ≦25A°+22.25°  (2)