Endoscope reprocessor and leak test method for endoscope reprocessor

An endoscope reprocessor includes: a recessed treatment tank 11 in which an endoscope is disposed; a cover 21 for covering the treatment tank 11; an open-to-atmosphere conduit 31 connected to the treatment tank 11 and opening the treatment tank 11 to the atmosphere; a gas filter connection unit 35 disposed in the open-to-atmosphere conduit 31; an opening and closing valve 34 provided in the open-to-atmosphere conduit 31 at a position closer to the treatment tank than the gas filter connection unit 35; a pressure sensor 41 for detecting pressure within the treatment tank 11; a pressurizing unit 51 either provided in the open-to-atmosphere conduit 31 at a position closer to the treatment tank than the opening and closing valve 34 or connected to the treatment tank 11, the pressurizing unit 51 pressurizing the treatment tank 11 even if the opening and closing valve 34 is in a closed state; and a control unit 61 for controlling the opening and closing valve 34 and the pressurizing unit 51. 内窥镜清洗消毒机包括：凹状的处理槽(11)，其