In an endoscope system having the function of capturing autofluorescence from a living body irradiated with excitation light and the function of capturing normal light observation images using white light as observation light, the normal light observation images are processed with a G fluorescence signal and an R fluorescence signal from the biological autofluorescence. The endoscope system produces bright images on which a lesion area can be easily identified in the endoscopic diagnosis using autofluorescence images.
