To provide an optical element which simultaneously has a successful antireflection effect by fine uneven periodic structure and an optical attenuation effect for attenuating predetermined wavelength.

The fine uneven periodic structure 23 in which innumerable conical projections 22 having pitch and height smaller than wavelength of a visible light region are arranged at equivalent intervals is formed on both sides of a transparent substrate 21. In addition, a black pigment is contained in the fine uneven periodic structure 23, thereby reflection on the surface of the substrate 21 is prevented by the fine uneven periodic structure and light with the wavelength of a visible light region is approximately uniformly attenuated by the black pigment.