Employed is an image processing device including a fluorescence-image generating unit that images fluorescence generated at a subject irradiated with excitation light and generates a fluorescence image; a white-light-image generating unit that images white light returned from the subject irradiated with illumination light and generates a white-light image; a memory that converts the white-light image to a plurality of color signals constituting a color space; an image computing unit that corrects the plurality of color signals converted by the memory using at least one color signal among the plurality of the color signals and the fluorescence image; an image computing unit that generates a corrected image from the plurality of color signals corrected by the image computing unit; and an image combining unit that combines the fluorescence image generated by the fluorescence-image generating unit and the corrected image generated by the image computing unit.