An endoscope cleaning/disinfecting apparatus of the invention is an endoscope cleaning/disinfecting apparatus which performs processing on an endoscope in a processing tank having an opening portion, the apparatus including a lid member which opens and closes the opening portion； a sealing member which is sandwiched between the lid member and the processing tank in a state where the lid member is located at a sealing position, an electric actuator which drives the lid member between the sealing position and an open position, and a control section which causes the electric actuator to continue to generate a pressing force for pressing the sealing member by the lid member toward the opening portion in a predetermined period during execution of the processing, and causes the electric actuator to stop generating the pressing force in a period other than the predetermined period.
