An optical element is provided with an optical layer in which a concavo-convex surface is formed on the surface thereof, and a wavelength-selective reflection layer formed on the concavo-convex surface. The wavelength-selective reflection layer directionally reflects light having a specific wavelength band selectively, while transmitting light having wavelength bands other than the specific wavelength band. The concavo-convex surface is provided with a plurality of first structural elements that are extended in a first direction within the surface of the optical layer and a plurality of second structural elements that are extended in a second direction within the surface of the optical layer, and placed to be spaced apart from each other, with the first direction and the second direction intersecting with each other.