An endoscope system includes an endoscope including a control section, an insertion section, and a light guide member, a light source configured to emit light guided by the light guide member, a failure-cause detecting circuit configured to detect a pre-failure state that causes a failure of the endoscope, and a light source controller configured to control an output of the light source based on a detection result of the failure-cause detecting circuit. The failure-cause detecting circuit includes a cause predicting circuit configured to detect a second pre-failure state in which it is predicted that the endoscope reaches a first pre-failure state that directly causes the failure of the endoscope. The light source controller controls the output of the light source based on a detection result of the cause predicting circuit.
