An endoscope cleaning/disinfecting apparatus connector configured to connect an endoscope and an endoscope cleaning/disinfecting apparatus, comprising: a cleaning/disinfecting apparatus connection section connectable to the endoscope cleaning/disinfecting apparatus; a circulating section, a first end of which is adapted to communicate with the cleaning/disinfecting apparatus connection section, and in which a fluid supplied from the cleaning/disinfecting apparatus circulates; and a discharge section (4, 24) that is provided at another end of the circulating section to be connectable to a pipe sleeve (11, 21) of the endoscope, and discharges the fluid which passes through the circulating section to the endoscope, wherein the discharge section (4, 24) comprises: a channel member connectable to a second end of the circulating section, a first channel (A1, A2, A1', A2') provided inside the channel member and configured to communicate with the circulating section and to discharge the fluid which passes through the circulating section into the pipe sleeve (11, 21) of the endoscope; a second channel that branches, at a branch section, from the first channel (A1, A2, A1' A2') and discharges the fluid which passes through the circulating section to a periphery of the pipe sleeve (11, 21) of the endoscope; an opening/closing section (6, 26) that is provided at the branch section and is configured to be freely expandable/contractible according to a flow rate of the fluid, to expand when the flow rate of the fluid is a predetermined amount or higher, and to close the second channel; and a first water control section (7b, 27b) that is provided at a distal end side of the first channel (A1, A2, A1', A2') of the channel member and is configured to repel the flow of the fluid, characterized in that the discharge section (4, 24) further comprises: at least one opening (7c, 27c) that is provided on an outer circumferential side of the channel member (7, 27) and is configured to exhaust the fluid repelled by the first water control section; and a second water control section that is provided at a position facing the opening in the branch section and is configured to branch the fluid exhausted from the opening to the second channel, wherein the opening/closing section is positioned between the opening and the second water control section. a cleaning/disinfecting apparatus connection section connectable to the endoscope cleaning/disinfecting apparatus; a circulating section, a first end of which is adapted to communicate with the cleaning/disinfecting apparatus connection section, and in which a fluid supplied from the cleaning/disinfecting apparatus circulates; and a discharge section (4, 24) that is provided at another end of the circulating section to be connectable to a pipe sleeve (11, 21) of the endoscope, and discharges the fluid which passes through the circulating section to the endoscope, a channel member connectable to a second end of the circulating section, a first channel (A1, A2, A1', A2') provided inside the channel member and configured to communicate with the circulating section and to discharge the fluid which passes through the circulating section into the pipe sleeve (11, 21) of the endoscope; a second channel that branches, at a branch section, from the first channel (A1, A2, A1' A2') and discharges the fluid which passes through the circulating section to a periphery of the pipe sleeve (11, 21) of the endoscope; an opening/closing section (6, 26) that is provided at the branch section and is configured to be freely expandable/contractible according to a flow rate of the fluid, to expand when the flow rate of the fluid is a predetermined amount or higher, and to close the second channel; and a first water control section (7b, 27b) that is provided at a distal end side of the first channel (A1, A2, A1', A2') of the channel member and is configured to repel the flow of the fluid, at least one opening (7c, 27c) that is provided on an outer circumferential side of the channel member (7, 27) and is configured to exhaust the fluid repelled by the first water control section; and a second water control section that is provided at a position facing the opening in the branch section and is configured to branch the fluid exhausted from the opening to the second channel, wherein the opening/closing section is positioned between the opening and the second water control section.