An ultrasound endoscope includes: an insertion portion configured to be inserted into a living body； an ultrasound transmitting and receiving unit； a balloon surrounding the ultrasound transmitting and receiving unit； a water supply port for supplying water to the balloon； an operating unit provided at a proximal end side of the insertion portion； a cable extending from the operating unit； a channel provided in the insertion portion and leading to the water supply port to supply water toward the water supply port； a pipe provided in the cable； a cylinder provided at the operating unit, one end of the channel and one end of the pipe being opened to the cylinder； an injection port provided in the pipe； and a duct having one end leading to the pipe via the injection port and having the other end to which a syringe for injecting water or supplying air is attachable.
