An endoscope cleaning/disinfecting apparatus connector according to the present invention includes a cleaning/disinfecting apparatus connection section, a circulating section 2 and a discharge section 4, wherein the discharge section 4 communicates with the circulating section 2 and includes a first channel A1, A2 that discharges a fluid R that passes through the circulating section 2 into a pipe sleeve 11, a second channel B that branches from the first channel A1, A2 and discharges the fluid R to the periphery of the pipe sleeve 11, and an opening/closing section 6 that is provided in a branch section 8 that branches from the first channel A1, A2 to the second channel B or in the second channel B, is freely expandable/contractible according to a flow rate of a fluid R and blocks the second channel B when the flow rate of the fluid R is a predetermined amount or higher.