Abstract: An endoscope system and an operation method thereof capable of reducing visual discomfort even when normal images and special images are alternately displayed. When the observation target including the first structure is illuminated with the first mode illumination light, a first mode display image obtained by imaging the observation target is acquired. When the observation target is illuminated with the second mode illumination light, a second mode display image obtained by imaging the observation target is acquired. The first mode display image or the second mode display image or the second mode display image or the second mode display image or the second mode display image before the correction so that the difference becomes smaller with respect to the difference in the color and / or the brightness of the first structure. The mode display image is corrected to obtain a corrected image.
