Provided are a polarized light splitting element, a method of manufacturing the same, a light radiating device, a method of radiating light, and a method of manufacturing an ordered photo-alignment film. The polarized light splitting element has excellent durability with respect to UV rays and heat, and low pitch dependence of polarization characteristics, so that it is easily manufactured. In addition, the polarized light splitting element may realize a high polarization degree and extinction ratio even in a short wavelength region.