Provided is a diffractive optical element (1) that is formed by laminating two optical material layers (2 and 3) formed of different energy-cured resins； in which a relief pattern (4) is formed at the interface between the two optical material layers (2 and 3)； and that satisfies the following conditional expressions:wherein d1 is the center plate thickness (mm) of one optical material layer 2 that is cured first, d2 is the center plate thickness (mm) of the other optical material layer 3 that is cured later, and φE is the effective diameter (mm) of the relief pattern 4.
