The endoscope reprocessor of the present invention is provided in the chemical solution tank for storing the chemical solution, and holds the densitometer so that the measurement surface of the concentration meter is disposed in the chemical solution tank. A first attachment / detachment unit, a storage solution tank for storing the storage solution of the densitometer, and the storage solution tank, wherein the measurement surface of the concentration meter is detachably attached to the storage solution tank. A second attaching / detaching portion for holding the densitometer.本発明の内視鏡リプロセッサは、薬液を貯留する薬液タンクと、前記薬液タンクに設けられ、濃度計の測定面が前記薬液タンク内に配置されるように着脱可能に前記濃度計を保持する第1着脱部と、前記濃度計の保存液を貯留する保存液タンクと、前記保存液タンクに設けられ、前記濃度計の測定面が前記保存液タンク内に配置されるように着脱可能に前記濃度計を保持する第2着脱部と、を含む。