A pixel-interpolation processing unit generates a sensitivity level value of an insufficient color component according to interpolation processing of image signals. A sensitivity level value of an insufficient color component in a pixel of attention is calculated, according to an arithmetic operation corresponding to an acquired color component of the pixel of attention, by assuming a geometric figure including sensitivity level values of acquired color components as vertexes. As the geometric figure, the same figure is used irrespectively of which color component the acquired color component is.