An electronic endoscope system (11, 76, 86, 101) comprising: an illumination section (14, 104) adapted to apply illumination light to a portion to be observed inside a body, the portion including a surface blood vessel and a subsurface blood vessel located deeper than the surface blood vessel, one of the surface blood vessel and the subsurface blood vessel being a target blood vessel to be observed, the other blood vessel being a non-target blood vessel, the illumination light including blue light and green light, light absorption by the surface blood vessel being larger in a wavelength range of the blue light, light absorption by the subsurface blood vessel is larger in a wavelength range of the green light; an imaging section (21, 102) adapted to capture reflection light reflected from the portion, having a color image sensor, that has at least a first color filter corresponding to blue light, a second color filter corresponding to green light and a third color filter corresponding to red light on each pixel, the red light being a smaller quantity of light absorbed by hemoglobin compared to blue and green light, and the color image sensor is adapted to output a blue imaging signal, a green imaging signal and a red imaging signal, and an image generating section adapted to generate an image, characterized by a suppression section (60, 103, 68) adapted to reduce contrast of the subsurface blood vessel in the green imaging signal by adding the red imaging signal to the green imaging signal, wherein the image generation section is adapted to generate an image based on at least the green imaging signal to which the red imaging signal is added and the blue imaging signal, or a suppressing section (60, 103, 68) adapted to reduce contrast of the surface blood vessel in the blue imaging signal by adding the red imaging signal to the blue imaging signal, wherein the image generating section is adapted to generate an image based on at least the blue imaging signal to which the red imaging signal has been added, and the green imaging signal. an illumination section (14, 104) adapted to apply illumination light to a portion to be observed inside a body, the portion including a surface blood vessel and a subsurface blood vessel located deeper than the surface blood vessel, one of the surface blood vessel and the subsurface blood vessel being a target blood vessel to be observed, the other blood vessel being a non-target blood vessel, the illumination light including blue light and green light, light absorption by the surface blood vessel being larger in a wavelength range of the blue light, light absorption by the subsurface blood vessel is larger in a wavelength range of the green light; an imaging section (21, 102) adapted to capture reflection light reflected from the portion, having a color image sensor, that has at least a first color filter corresponding to blue light, a second color filter corresponding to green light and a third color filter corresponding to red light on each pixel, the red light being a smaller quantity of light absorbed by hemoglobin compared to blue and green light, and the color image sensor is adapted to output a blue imaging signal, a green imaging signal and a red imaging signal, and an image generating section adapted to generate an image, characterized by a suppression section (60, 103, 68) adapted to reduce contrast of the subsurface blood vessel in the green imaging signal by adding the red imaging signal to the green imaging signal, wherein the image generation section is adapted to generate an image based on at least the green imaging signal to which the red imaging signal is added and the blue imaging signal, or a suppressing section (60, 103, 68) adapted to reduce contrast of the surface blood vessel in the blue imaging signal by adding the red imaging signal to the blue imaging signal, wherein the image generating section is adapted to generate an image based on at least the blue imaging signal to which the red imaging signal has been added, and the green imaging signal.