Provided is a diffusion sheet having a function for preventing warping, and having excellent optical and diffusion characteristics. A diffusion sheet 1 has a minute roughness pattern formed on the surface thereof, the pattern configured such that first protrusions 3a having a first height and second protrusions 3b having a second height lower than the first height are disposed in parallel. A portion of the first protrusions 3a is bonded to a bonding layer on the rear surface of an upper-layer sheet laminated on the surface of a diffusion sheet 2, and the second protrusions 3b are not bonded to said bonding layer. The following relationships are satisfied: h1:h2=1:0.5-0.1, and w1:w2=1:1.0-0.1, where h1 is the height of the first protrusions 3a, w1 is the width of the first protrusions 3a, h2 is the height of the second protrusions 3b, and w2 is the width of the second protrusions 3b.