An endoscope cleaning/disinfecting apparatus has a cleaning tank in which an endoscope is disposed, a chemical tank that stores a chemical solution, a water supply connecting portion that is connectable to a water service pipe, an endoscope cleaning/disinfecting section having a first conduit that connects the cleaning tank and the chemical tank, and a second conduit that connects the cleaning tank and the water supply connecting portion, an operation panel that is a water information input section to which hardness information of water that is supplied from the water service pipe is inputted, a memory that is a history information retaining section that retains cleaning history information of the endoscope cleaning/disinfecting section, and a control section that is a determination section that determines necessity or nonnecessity of scale removal of the endoscope cleaning/disinfecting section based on the hardness information and the cleaning history information.