An endoscope system is a light source device capable of supplying an excitation light for generating fluorescence, reference light having a wavelength band different from fluorescence, an objective optical system, an optical filter for interrupting reflected light of excitation light, and a fluorescent light emitted through an optical filter An observation image for generating an observation image using first to third signals obtained by imaging an image pickup section separated into light, a light of a first wavelength band and a light in a second wavelength band, and a light of a first wavelength band and light of a second wavelength band The display unit and the first signal are assigned to the green component of the display device, and among the second and third signals, a signal having a relatively large signal value is assigned to the red component of the display device, and a signal having a relatively small signal value is displayed. A control unit for assigning the blue component to the blue component is provided.内視鏡システムは、蛍光を発生させるための励起光と、蛍光とは異なる波長帯域の参照光と、を供給可能な光源装置と、対物光学系と、励起光の反射光を遮断する光学フィルタと、光学フィルタを経て出射される光を、蛍光と、第1の波長帯域の光と、第2の波長帯域の光と、に分離して撮像する撮像部と、蛍光と、第1の波長帯域の光と、第2の波長帯域の光と、を撮像して得られた第1~第3の信号を用いて観察画像を生成する観察画像生成部と、第1の信号を表示装置の緑色成分に割り当てさせ、第2及び第3の信号のうち、相対的に大きな信号値を有する信号を表示装置の赤色成分に割り当てさせ、かつ、相対的に小さな信号値を有する信号を表示装置の青色成分に割り当てさせる制御部と、を有する。
