An imaging device has an image sensor, and a color filter that is located on said image sensor and has at least four color elements, a signal reading processor that reads at least four series of color signals corresponding to the at least four color elements from said image sensor, and a signal processor that generates primary color signals on the basis of at least one predetermined series of color signals and an adopted series of color signals that is obtained from the remaining series of color signals. The signal processor defines a series of color signals that corresponds to a spectral response distribution curve over wavelength range for which spectral values in the spectral distribution of the object are relatively large, as the adopted series of color signals.