Abstract: There is provided an optical sheet for use as a display device surface, which has a functional layer on at least one side of a transparent base material and has a diffusion factor on the outer surface and/or interior of the functional layer, wherein the relationship represented by the following formula (I) is satisfied. 2.1<Q/U<21.4??(I) Q (regular transmission intensity): Diffuse transmission intensity at 0 degrees. U (virtual regular transmission intensity): Transmission intensity which is a straight line connecting the transmission intensities at diffusion regular transmission ±2 degrees and diffusion regular transmission ±1 degree, extrapolated from the diffuse regular transmission angle.