An optical body includes a substrate having a concave-convex surface, a reflecting layer formed on the concave-convex surface, and an optical layer formed on the reflecting layer to embed the concave-convex surface, wherein the reflecting layer directionally reflects light, the concave-convex surface is made up of a plurality of triangular pillars arrayed in a one-dimensional pattern, and the triangular pillar has an apex angle α and a slope angle β, the apex angle α and the slope angle β satisfying a formula (1) or (2) given below: 30≦β≦4.5α−285(70≦α≦80)  (1) 30≦β≦−1.5α+195(80≦α≦100)  (2).