A light diffusion sheet 43 includes, at least in its first surface 43a, a plurality of recesses 22 formed in a substantially inverted polygon pyramid or in a substantially inverted truncated polygon pyramid. The ridge 23 parting the plurality of recesses 22 has a recessed shape between the intersections 23a, with respect to a straight line connecting the intersections 23a of the ridge 23. Where P is the arrangement pitch of the plurality of recesses 22 and Wr is the dimension occupied by a curved portion at the top portion of the ridge 23 in the arrangement direction of the plurality of recesses 22, a ratio Wr/P is 0.3 or less. The maximum height difference d between the ridge 23 and the straight line connecting the intersections 23a of the ridge 23 is 1 μm or more and 10 μm or less.