PROBLEM TO BE SOLVED: To provide an endoscope system, an endoscope adapter, and an endoscope connector which can make a soluble gas having solubility to a liquid supplied into a balloon a gas to be jetted from the tip of an insertion part without significantly changing a duct line configuration of an existing ultrasonic endoscope, and prevent deterioration in image quality of an ultrasonic image.SOLUTION: A liquid storage tank 22 which supplies water via an adapter 80 and a gas supply device 74 which supplies a carbon dioxide gas are connected to a water-feeding connector 64 in a connector part 15 of an ultrasonic endoscope 10. With this, the carbon dioxide gas can be supplied from the gas supply device 74 to an air-blowing/water-feeding nozzle 18, and water can be supplied from the liquid storage tank 22 to the air-blowing/water-feeding nozzle 18 and the balloon 21. Also, air can be supplied from an air-blowing pump 37 to the liquid storage tank 22, as a pressurizing gas.SELECTED DRAWING: Figure 1
