A photoelectric conversion device including a photoelectric converter, a transparent cover, an insulating material layer and a photonic crystal layer is provided. The photoelectric converter is adapted to receive a light. The transparent cover is disposed on a side of the photoelectric converter. The insulating material layer is disposed between the photoelectric converter and the transparent cover. The photonic crystal layer is disposed between the insulating material layer and the transparent cover, wherein the material of the photonic crystal layer is different from the material of the insulating material layer.