To provide an optical element that transmittance characteristic to variations of an incident angle on a multi-layer film is little in the direction of the wavelength.

This optical element is configured by forming a multi-layer optical film 12 by alternately laminating a high refractive film with a refractive index of ≥2.0 and a low refractive film with a refractive index of ≤1.6 and is arranged so that an optical film thickness ratio of a main film having a periodic structure satisfies (nH×dH)/(nL×dL)≥2...(1), when the refractive index of the high refractive film is expressed by nH, that of the low refractive film by nL, the film thickness of the high refractive film is expressed by dH, and that of the low refractive film by dL.