To provide a two-dimensional viewing angle expansion member which is free of a decrease in surface luminance and a decrease in contrast due to stray light, and has small angle dependence and small scatter reflection of external light, and a display device using the two-dimensional viewing angle expansion member.

Two light diffusion sheets each having a plurality of substantially trapezoidally sectioned unit lenses formed linearly are put one over the other with unit lenses aligned at substantially 90° to each other. Each of the light diffusion sheets has unit lenses each formed having a light incidence part as the bottom base of a trapezoid, a light emission part as the top base, and total reflection parts as oblique sides. The unit lenses of the respective light diffusion sheets are made of high-refractive-index material, and triangularly-sectioned parts sandwiched between adjacent unit lenses are made of low-refractive-index material having a lower refractive index than the high-refractive-index material. Light absorbing particles are added to the low-refractive-index material, and the amount of the light absorbing particles to the low-refractive-index material is 10-60 mass%.