In the present invention, characteristic artifacts are corrected in the case of magnified observation by means of an oxygen saturation image. This endoscope system (10) is provided with an image generation unit (84), a low-frequency component extraction unit (103), a high-frequency component extraction unit (101), and a combining process unit (104). The image generation unit (84) generates a first oxygen saturation image on the basis of a first image signal obtained by imaging a specimen and the oxygen saturation calculated on the basis of the first image signal. Also, the image generation unit (84) generates a second image signal obtained by imaging the specimen magnified more than during the output of the first image signal, and a second oxygen saturation image that is on the basis of the oxygen saturation calculated on the basis of the second image signal. The low-frequency component extraction unit (103) extracts the low-frequency component that is less than a cutoff frequency from the first oxygen saturation image, and the high-frequency component extraction unit (101) extracts a high-frequency component that is at least the cutoff frequency from the second oxygen saturation image. The combining process unit (104) generates a combined oxygen saturation image resulting from combining same.
