An optical body having an incident surface S1 and an emergent surface S2 comprising: a first optical layer having a concave-convex surface; a wavelength selective reflecting layer formed on the concave-convex surface; and a second optical layer formed on the wavelength selective reflecting layer and embedding the concave-convex surface, wherein the wavelength selective reflecting layer selectively directionally reflects light in a particular wavelength band while transmitting light other than the particular wavelength band therethrough, the concave-convex surface is made up of a plurality of triangular pillars arrayed in a one-dimensional pattern, wherein the triangular pillar has a first sloped surface Sp1 and a second sloped surface Sp2, the triangular pillar has an apex angle α, formed by the first sloped surface Sp1 and the second sloped surface Sp2, and a slope angle β of the first sloped surface Sp1 with respect to the incident surface S1 or the emergent surface S2, and the apex angle α and the slope angle β satisfying a formula given below: α − 30 ≤ β ≤ − α + 170 for 90 ≤ α ≤ 100 a proportion of a film thickness d2 of the wavelength selective reflecting layers formed on the second sloped surface Sp2 to a film thickness d1 of the wavelength selective reflecting layers formed on the first sloped surface Sp1 deviates from 100% by ± 10% or less, a transmission image clarity measured for the light of transmission wavelengths in conformity with JIS K-7105 by using an optical comb of 0.5 mm is 50 or more, the difference in refractive index between the first optical layer and the second optical layer is 0.010 or less, the wavelength selective reflecting layer is a multilayer film formed by alternately stacking a metal layer having a high reflectance in the infrared range, and a high refractive index layer having a high refractive index in the visible range and serving as an anti-reflection layer, the metal layer containing, as a main component, Au, Ag, Cu, Al, Ni, Cr, Ti, Pd, Co, Si, Ta, W, Mo or Ge alone, or an alloy containing two or more selected from among those elements, the wavelength selective reflecting layer is formed on the entire concave-convex surface, wherein the arithmetic mean roughness Ra of the incident surface S1 and the arithmetic mean roughness Ra of the emergent surface S2 measured in conformity with JIS B0601:2001 is 0.08 μm or less, and wherein, when the optical body is affixed to a window member at the side of the first optical layer, the first sloped surface Sp1 becomes a surface positioned on the upper side (sky side), and the second sloped surface Sp2 becomes a surface positioned on the lower side (ground side). a first optical layer having a concave-convex surface; a wavelength selective reflecting layer formed on the concave-convex surface; and a second optical layer formed on the wavelength selective reflecting layer and embedding the concave-convex surface, wherein the wavelength selective reflecting layer selectively directionally reflects light in a particular wavelength band while transmitting light other than the particular wavelength band therethrough, the concave-convex surface is made up of a plurality of triangular pillars arrayed in a one-dimensional pattern, wherein the triangular pillar has a first sloped surface Sp1 and a second sloped surface Sp2, the triangular pillar has an apex angle α, formed by the first sloped surface Sp1 and the second sloped surface Sp2, and a slope angle β of the first sloped surface Sp1 with respect to the incident surface S1 or the emergent surface S2, and the apex angle α and the slope angle β satisfying a formula given below: α − 30 ≤ β ≤ − α + 170 for 90 ≤ α ≤ 100 a proportion of a film thickness d2 of the wavelength selective reflecting layers formed on the second sloped surface Sp2 to a film thickness d1 of the wavelength selective reflecting layers formed on the first sloped surface Sp1 deviates from 100% by ± 10% or less, a transmission image clarity measured for the light of transmission wavelengths in conformity with JIS K-7105 by using an optical comb of 0.5 mm is 50 or more, the difference in refractive index between the first optical layer and the second optical layer is 0.010 or less, the wavelength selective reflecting layer is a multilayer film formed by alternately stacking a metal layer having a high reflectance in the infrared range, and a high refractive index layer having a high refractive index in the visible range and serving as an anti-reflection layer, the metal layer containing, as a main component, Au, Ag, Cu, Al, Ni, Cr, Ti, Pd, Co, Si, Ta, W, Mo or Ge alone, or an alloy containing two or more selected from among those elements, the wavelength selective reflecting layer is formed on the entire concave-convex surface, wherein the arithmetic mean roughness Ra of the incident surface S1 and the arithmetic mean roughness Ra of the emergent surface S2 measured in conformity with JIS B0601:2001 is 0.08 μm or less, and wherein, when the optical body is affixed to a window member at the side of the first optical layer, the first sloped surface Sp1 becomes a surface positioned on the upper side (sky side), and the second sloped surface Sp2 becomes a surface positioned on the lower side (ground side).