Provided are a color separation element and an image sensor including the same. The color separation element includes a spacer layer; and a color separation lens array, which includes at least one nano-post arranged in the spacer layer and is configured to form a phase distribution for splitting and focusing incident light according to wavelengths, wherein periodic regions in which color separation lens arrays are repeatedly arranged are provided, and the color separation lens array is configured to interrupt phase distribution at the boundary of the periodic regions.