An endoscope system includes: an endoscope including an insertion portion whose front end is inserted inside a subject； a heater disposed at the front end and configured to heat a predetermined member disposed at the front end； a plurality of thermometers disposed near the predetermined member at the front end and configured to detect temperatures at the front end； a power source configured to supply electrical power to the heater； determination circuitry configured to determine whether or not highest temperature, from among the temperatures detected by the plurality of thermometers, is equal to or higher than a first threshold value； and a power controller configured to control, based on determination result of the determination circuitry, the electrical power supplied by the power source to the heater.
