Provided is an ultrasonic endoscope capable of efficiently cleaning a supply / discharge pipe path with a cleaning brush while reducing a diameter and a size of a distal end portion of an insertion portion to be inserted into a body cavity. The ultrasonic endoscope includes an insertion portion 20 having a distal end, a proximal end, and a longitudinal axis, an ultrasonic transducer 62 provided at the distal end of the insertion portion 20, and an ultrasonic transducer disposed on the proximal side of the ultrasonic transducer 62, A locking groove 68 which is a balloon attachment portion to which the balloon 64 enclosing the ultrasonic transducer 62 is detachably attached, a balloon conduit 104 extending to the inside of the insertion portion 20, a distal end side , And is provided toward the distal direction starting from the distal end side opening surface 70 and the distal end side opening surface 70 of the balloon conduit 104 having the normal component in the longitudinal direction and at least a part in the longitudinal axial direction And a groove portion 74 which overlaps the ultrasonic transducer 62.体腔内に挿入される挿入部の先端部の細径化、小型化を図りつつ、給排管路を洗浄ブラシで効率的に洗浄することが可能な超音波内視鏡を提供する。超音波内視鏡は、先端と基端と長手軸とを有する挿入部20と、挿入部20の先端に設けられた超音波トランスデューサ62と、超音波トランスデューサ62よりも基端側に配置され、超音波トランスデューサ62を包むバルーン64が着脱自在に装着されるバルーン装着部である係止溝68と、挿入部20の内部に延設されたバルーン管路104と、係止溝68よりも先端側に設けられ、長手軸方向の法線成分を有する、バルーン管路104の先端側開口面70と、先端側開口面70を起点として先端方向に向かって設けられ、長手軸方向において少なくとも一部が超音波トランスデューサ62と重複する溝部74と、を備える。
