An imaging device includes an image sensor to convert an optical image of a subject into an electric signal, an image processor to generate an image according to the electric signal, an image synthesizer to synthesize, pixel-by-pixel, images generated by the image processor in a same composition under a same condition, a digital clamp processor to perform a digital clamp to remove an offset component from a synthesized image obtained by the image synthesizer, and a digital clamp controller to control a digital clamp amount of the digital clamp processor on the basis of a number of images synthesized by the image synthesizer.