A color separation element array includes color separation elements which are two-dimensionally arranged to separate an incident light according to a wavelength such that a light of a first wavelength is directed to a first direction and a light of a second wavelength that is different from the first wavelength is directed to a second direction that is different from the first direction. Each of the color separation elements includes a first element and a second element that are sequentially arranged along a traveling direction of the incident light, and the first element and the second element of the color separation elements are symmetrically shifted with respect to a center area of the color separation element array, to be aligned to fit to the traveling direction of the incident light that is obliquely incident.