An endoscope cleaning/disinfecting apparatus includes: a cleaning/disinfecting tank, a lid portion, an accommodation detecting section, an opening/closing detecting section, a cleaning/disinfecting section, a cleaning/disinfection detecting section, an informing section, a judging section judging a case where the opening/closing detecting section detects a closed state of the lid portion before the cleaning/disinfection detecting section detecting driving of the cleaning/disinfecting section after the accommodation detecting section detecting that an endoscope is accommodated in the cleaning/disinfecting tank as a first closed state； and a control section performing control of driving the informing section to issue a warning when the opening/closing detecting section detects an opened state of the lid portion before the cleaning/disinfection detecting section detecting driving of the cleaning/disinfecting section after the judging section detecting the first closed state.
