PROBLEM TO BE SOLVED: To provide an endoscope system capable of displaying images realizing depth feeling throughout the entire interior of a body cavity while performing natural color reproduction substantially equivalent to what is seen in normal light observation with the naked eye, and also to provide an operation method for the endoscope system.SOLUTION: A light source unit emits first blue light from B1-LED20a, emits green light from G-LED20c, and emits red light from R-LED20d. A light source control unit 21 performs first specific light emission control for the green light and red light. An imaging sensor 48 illuminates and images an observation object within a body cavity with the light emitted from the light source unit under the first specific light emission control. A signal output unit outputs a blue signal, a green signal, and a red signal, the red signal having at least two peaks in a histogram in which frequencies and pixel values are plotted along the horizontal and vertical axes, respectively. A display control unit 68 assigns the blue signal, green signal, and red signal to any of a B channel, a G channel, and an R channel of a monitor 18.SELECTED DRAWING: Figure 2
