An endoscope system includes: a phosphor and first and second blue laser light sources that emit first white light and second white light having different emission spectrums a sensor that images an observation target under illumination with the first white light and outputs a first image signal and images the observation target under illumination with the second white light and outputs a second image signal a movement amount calculation unit that calculates the movement amount of the observation target based on the first or second image signal and an oxygen saturation calculation unit that calculates the oxygen saturation based on the movement amount in at least one of a first mode, in which the oxygen saturation is calculated using the first and second image signals, and a second mode, in which the oxygen saturation is calculated using the first image signal.
