An endoscope system according to the present invention has an illuminator configured to illuminate an object to be observed with normal light, the illuminator being capable of emitting a plurality of narrow-band light having different peak wavelengths, respectively； an image processor that generates an observed image from one frame/field worth of image-pixel signals, the image-pixel signals being read from an image sensor provided in the tip portion of a video scope, the image processor generating a plurality of spectral images in accordance to the emission of the plurality of narrow-band light； a detector that detects an operator's aiming spot with respect to at least the plurality of spectral images； a determiner that determines a diagnosis object area that contains the detected aiming spot； and a spectral image processor that extracts a diseased portion with spectral characteristics different from those of the other portions, among the plurality of diagnosis object areas that are defined within the plurality of spectral images, the image processor generating a diagnosis image that distinguishes the diseased portion from the other image portions.
