PROBLEM TO BE SOLVED To provide a technique capable of more appropriately adjusting the luminance of an endoscopic image.A peak detection unit for detecting a first peak and a second peak in order from a high luminance side from a pixel number distribution for each luminance of an endoscopic image based on imaging by an image sensor, And an exposure control unit that performs exposure control based on the first brightness difference of the first peak and the first brightness difference of the second peak.BACKGROUND OF THE INVENTION