To provide an optical element in which the diffraction efficiency in each use wavelength region within the entire visible region is preferable, and light beams of a specific order (design order) are sufficiently concentrated in the entire use wavelength region, by using an optical material in which the relationship between a refraction index n_d and an Abbe number _d with respect to a "d" line is n_d-6.66710^-3_d+1.70 and the Abbe number _d satisfies _d16.