An endoscope apparatus of the invention includes an endoscope, camera control unit (CCU), and a trocar. The endoscope includes a heater and a temperature sensor. The CCU is configured to include a resistance value-voltage value conversion section, an analog-digital conversion section, voltage value-temperature table conversion section, a control voltage calculation section, an digital-analog conversion section, a voltage amplification section, a switch control section, and a switch. The trocar 5 includes an insertion detection sensor.