A color separation element array comprising: color separation elements which are two-dimensionally arranged across a plane and configured to separate an incident light according to a wavelength such that, of the incident light, 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; wherein each of the color separation elements comprises a first element and a second element that are arranged in the direction normal to the plane to be sequentially arranged along a traveling direction of the incident light; the first element and the second element of at least one of the color separation elements are offset with respect to each other in the two dimensions of the plane; the first element and the second element of one of the color separation elements, which is arranged in the center area of the color separation element array, are aligned with one another with no offset, such that center portions of the first element and the second element are aligned, and the first elements and the second elements of respective color separation elements, which are arranged in an area other than the center area of the color separation element array, have an offset with respect to one another, forming offset pairs each comprising respective first and second elements; and an offset amount between the first element and second element of respective color separation elements increases as a distance from a center area of the color separation element array to the respective color separation elements increases, the color separation element array further comprising a transparent dielectric layer, wherein the color separation elements are buried in the transparent dielectric layer, and a first refractive index of the first elements and a second refractive index of the second elements are greater than that of the transparent dielectric layer. color separation elements which are two-dimensionally arranged across a plane and configured to separate an incident light according to a wavelength such that, of the incident light, 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; wherein each of the color separation elements comprises a first element and a second element that are arranged in the direction normal to the plane to be sequentially arranged along a traveling direction of the incident light; the first element and the second element of at least one of the color separation elements are offset with respect to each other in the two dimensions of the plane; the first element and the second element of one of the color separation elements, which is arranged in the center area of the color separation element array, are aligned with one another with no offset, such that center portions of the first element and the second element are aligned, and the first elements and the second elements of respective color separation elements, which are arranged in an area other than the center area of the color separation element array, have an offset with respect to one another, forming offset pairs each comprising respective first and second elements; and an offset amount between the first element and second element of respective color separation elements increases as a distance from a center area of the color separation element array to the respective color separation elements increases, the color separation element array further comprising a transparent dielectric layer, wherein the color separation elements are buried in the transparent dielectric layer, and a first refractive index of the first elements and a second refractive index of the second elements are greater than that of the transparent dielectric layer.