An endoscope system comprising: an image acquisition unit configured to acquire an observation image; a display control unit configured to cause a display unit to automatically switch and display at least two first and second observation images acquired by the image acquisition unit for display, in which the same object to be observed is displayed, for a display period of at least two or more frames, wherein first spectral information of the first observation image for display and second spectral information of the second observation image for display are different from each other; a light source unit configured to emit first illumination light having the first spectral information and second illumination light having the second spectral information; a light source control unit configured to cause each of the first illumination light and the second illumination light to be emitted for a light emission period and automatically switches the first illumination light and the second illumination light, wherein the first observation image for display is obtained in a case where an image of the object to be observed illuminated with the first illumination light is picked up; the second observation image for display is obtained in a case where an image of the object to be observed illuminated with the second illumination light is picked up; characterized in that the light emission period is at least two or more frames, wherein the light source control unit is configured to make the color tone of at least a part of a background mucous membrane of the first observation image for display be the same as the color tone of at least a part of a background mucous membrane of the second observation image for display by making light intensity ratios of green light and red light in the first illumination light be the same as light intensity ratios of green light and red light in the second illumination light. an image acquisition unit configured to acquire an observation image; a display control unit configured to cause a display unit to automatically switch and display at least two first and second observation images acquired by the image acquisition unit for display, in which the same object to be observed is displayed, for a display period of at least two or more frames, wherein first spectral information of the first observation image for display and second spectral information of the second observation image for display are different from each other; a light source unit configured to emit first illumination light having the first spectral information and second illumination light having the second spectral information; a light source control unit configured to cause each of the first illumination light and the second illumination light to be emitted for a light emission period and automatically switches the first illumination light and the second illumination light, wherein the first observation image for display is obtained in a case where an image of the object to be observed illuminated with the first illumination light is picked up; the second observation image for display is obtained in a case where an image of the object to be observed illuminated with the second illumination light is picked up; characterized in that the light emission period is at least two or more frames, wherein the light source control unit is configured to make the color tone of at least a part of a background mucous membrane of the first observation image for display be the same as the color tone of at least a part of a background mucous membrane of the second observation image for display by making light intensity ratios of green light and red light in the first illumination light be the same as light intensity ratios of green light and red light in the second illumination light.