Endoscope reprocessor

An endoscope reprocessor includes: a processing tank including a first tank that is arranged at a lowermost tier, and a second tank that communicates with the first tank, the processing tank allowing an endoscope to be placed in the processing tank; a drainage port arranged in the first tank; a first water level detection section that detects whether or not a first water level set to be a water level that is equal to or below a boundary between the first tank and the second tank is submerged in water; a circulation port that opens at a level that is below the first water level; a circulation conduit including one end connected to the circulation port and another end that opens at a position that is above the first water level in the processing tank; and a circulation pump that is provided in the circulation conduit.