An endoscope system includes: an endoscope having an insertion section adapted to be inserted into a subject； an optical member positioned at a distal end portion； a heating section configured to heat the optical member； a first temperature detector configured to detect first temperature information of the distal end portion； a second temperature detector connected in parallel with the heating section and configured to detect second temperature information of the distal end portion； a control unit configured to control the heating section based on the first temperature information； and an abnormality determination unit configured to determine presence or absence of abnormality in the first temperature detector and the second temperature detector based on the first temperature information and the second temperature information.
