PROBLEM TO BE SOLVED: To provide an endoscope reprocessor capable of detecting an installation-state fault of a water filter part to the endoscope reprocessor.SOLUTION: An endoscope reprocessor 1 includes: a processing tank for disposing an endoscope； a water filter part 2 for filtering water； a duct 11 for connecting the water filter part 2 to a tap water supply source； an air pump 6 connected to the duct 11 and supplying the water filter part 2 with the air as fluid； a duct 13 for connecting a treatment tank and the water filter part 2； an on-off valve 5 disposed at the duct 13； a pressure sensor 4 for detecting a pressure between the on-off valve 5 out of the duct 13 and the water filter part 2； and a control part 7 for determining a connection state of the water filter part 2 to the duct 13 by comparing a change in the pressure detected by the pressure sensor 4, with a prescribed criterion.SELECTED DRAWING: Figure 1
