An endoscope system, comprising: an image signal acquisition means for acquiring an image signal by imaging a subject; a light source device used for imaging the subject that is able to generate white light and blue narrow-band light; a normal light image generation means for generating a normal light image, in which a wavelength component of a visible light region is included, based on the image signal, the normal light image being generated from a signal obtained by illuminating a subject only with white light; an irregularity image generation means for generating an irregularity image, that is an image of a superficial microstructure or hypertrophy, by extracting only information of irregularities on the subject from the image signal, the irregularity image being obtained by extracting a hypertrophy image when only white light illuminates the subject, or by extracting a superficial microstructure image when the subject is illuminated with white light and blue narrow-band light simultaneously; a first composite image generation means (61c, 62d) for generating a first composite image by combining the normal light image with the irregularity image; a blood vessel extraction image generation means for generating a blood vessel extraction image by extracting a blood vessel located at a specific depth in the subject based on the image signal acquired when only white light illuminates the subject; a second composite image generation means for generating a second composite image by combining the normal light image, the blood vessel extraction image, and the irregularity image; wherein the image signal is configured to include image signals of a plurality of colors including at least a blue signal, which has a blue light component having a degree of penetration to a surface layer of body tissue of the subject, and a green signal, which has a green light component having a degree of penetration to a medium-deep layer of the body tissue, and the blood vessel extraction image generation means extracts the blood vessel at the specific depth based on a ratio of the blue signal and the green signal of the image signals of the plurality of colors. an image signal acquisition means for acquiring an image signal by imaging a subject; a light source device used for imaging the subject that is able to generate white light and blue narrow-band light; a normal light image generation means for generating a normal light image, in which a wavelength component of a visible light region is included, based on the image signal, the normal light image being generated from a signal obtained by illuminating a subject only with white light; an irregularity image generation means for generating an irregularity image, that is an image of a superficial microstructure or hypertrophy, by extracting only information of irregularities on the subject from the image signal, the irregularity image being obtained by extracting a hypertrophy image when only white light illuminates the subject, or by extracting a superficial microstructure image when the subject is illuminated with white light and blue narrow-band light simultaneously; a first composite image generation means (61c, 62d) for generating a first composite image by combining the normal light image with the irregularity image; a blood vessel extraction image generation means for generating a blood vessel extraction image by extracting a blood vessel located at a specific depth in the subject based on the image signal acquired when only white light illuminates the subject; a second composite image generation means for generating a second composite image by combining the normal light image, the blood vessel extraction image, and the irregularity image; wherein the image signal is configured to include image signals of a plurality of colors including at least a blue signal, which has a blue light component having a degree of penetration to a surface layer of body tissue of the subject, and a green signal, which has a green light component having a degree of penetration to a medium-deep layer of the body tissue, and the blood vessel extraction image generation means extracts the blood vessel at the specific depth based on a ratio of the blue signal and the green signal of the image signals of the plurality of colors.