When the air supply pipe line 51 is connected to the space portion 32 inside the endoscope 2 and air is delivered and leak judgment is performed based on the change in the internal pressure of the endoscope 2 by this air, 60 maintains the surface temperature T of the endoscope 2 measured by the temperature measuring unit 6 at the temperature Tt at the time of start of the leak determination through energy supply control for irradiating far infrared rays to the surface of the endoscope 2.内視鏡2の内部の空間部32にエア供給管路51を接続して空気を送気し、この空気による内視鏡2の内圧の変化に基づいてリーク判定を行うに際し、遠赤外線照射部60から内視鏡2の表面に対して遠赤外線を照射するエネルギー供給制御を通じて、温度測定部6によって測定される内視鏡2の表面温度Tをリーク判定開始時の温度Ttに維持する。
