Provided is an optical diffraction element that restricts overall thickness of the element while maintaining strength. The optical diffraction element comprises a substrate; an orientation layer that is formed on one surface of the substrate and includes anisotropic polymers that are oriented perpendicular to or inclined relative to a surface of the substrate in at least a partial region of the orientation layer; and a liquid crystal layer formed on the orientation layer. The liquid crystal layer includes a plurality of orientation patterns that are formed periodically and include liquid crystal molecules having different orientation directions, and the orientation direction for at least some of the orientation patterns is perpendicular to or inclined relative to the surface of the substrate, as a result of aligning with the orientation of the orientation layer formed on a bottom surface of the orientation patterns.