An image processing device includes: an image acquiring unit configured to acquire a plurality of images that are captured with a same angle of view and are different from each other in a wavelength band of illumination light; a processor including hardware. The processor is configured to determine, based on a first image and a second image different from the first image in the plurality of images, whether a first light absorber in a living body in the first image and a second light absorber in a living body in the second image overlap in a depth direction of a living body, and extract light-absorption information as a result of absorption by the first light absorber, by using the first image, the second image, and a determination result.