Endoscope system

An endoscope system comprising:

• a light source apparatus configured to be capable of emitting excitation light for exciting a fluorescent medical agent administered to a subject and illuminating light for illuminating an inside of a body cavity of the subject;
• an image sensor configured to pick up an image of each of fluorescence emitted in response to application of the excitation light to an object present inside the body cavity of the subject to which the fluorescent medical agent is administered and reflected light emitted in response to application of the illuminating light to the object;
• and
• a mixed image generating circuit configured to generate an observation image in which a first image that is an image obtained by performing image pickup of the reflected light by the image sensor, and a second image that is an image indicating a site of emission of the fluorescence in the object are mixed in a set of pixel arrays that do not overlap each other and each have periodicity.