An endoscope system, wherein a processor reads out light distribution information which is information indicating a relationship between an arrangement of an image pickup device and a distribution of illumination light emission positions and which includes information about a light distribution angle of illumination light and the number of illuminating portions, a part of parameters of a light adjustment parameter and a parameter flag from an endoscope, and controls amounts of light of the illuminating portions by selecting the part of the parameters with priority over the light adjustment parameters at time of selecting the light adjustment parameter based on the light distribution information, if it is specified by the parameter flag that the part of the parameters are used for the light adjustment.