An image processing unit generates image data of an image based on an output signal from an imaging device, corrects the image data, and outputs corrected image data. An optical filter is structured such that an upper limit of a transmitting wavelength decreases as a distance from an optical axis of the imaging optical system increases on an imaging plane of the imaging device so that a light in an infrared region is transmitted on the optical axis and cut off at a position farthest away from the optical axis on the imaging plane. The image processing unit corrects the image data based on a correction equation corresponding to the upper limit of the transmitting wavelength.