PROBLEM TO BE SOLVED: To provide an ultrasonic endoscope, reducing the risk of accidentally pushing in a piston to a position where suction force is exerted on a balloon mounted to the tip end of an insertion part so that a balloon is contracted unintentionally.SOLUTION: An ultrasonic endoscope includes: a piston 48 slidable to cylinders 35 and 40 a movable body 54 which is located at a non-operation position when the piston is located between a close position and a suction pipe open position and slides together with the piston when the piston is located between the suction pipe open position and a balloon suction pipe open position first energizing means CS1 for energizing the piston to move toward the close position second energizing means CS2 for energizing the mover to move toward the non-operation position and balloon suction pipeline opening and closing O-rings L2, L3 and L4 which cut off the communication between the balloon suction pipeline and a suction source connecting pipeline when the piston is located between the close position and the suction pipe open position, and communicate the balloon suction pipeline with the suction source connecting pipeline when the piston is located on the balloon suction pipe open position.COPYRIGHT: (C)2014,JPO&INPIT【課題】挿入部の先端部に装着したバルーンに吸引力を及ぼす位置までピストンを誤って押し込み、意図せずにバルーンが縮んでしまうおそれを小さくできる超音波内視鏡を提供する。【解決手段】シリンダ35、40に対してスライド自在なピストン48と、ピストンが閉位置と吸引管開位置の間に位置するときは非作動位置に位置し、ピストンが吸引管開位置とバルーン吸引管開位置の間に位置するときはピストンと一緒にスライドする移動体54と、ピストンを閉位置に向けて移動付勢する第一付勢手段CS1と、移動体を非作動位置に向けて移動付勢する第二付勢手段CS2と、ピストンが閉位置と吸引管開位置の間に位置するときはバルーン吸引管路と吸引源接続管路との連通を遮断し、ピストンがバルーン吸引管開位置に位置するときはバルーン吸引管路と吸引源接続管路とを連通させるバルーン吸引管路開閉用OリングL2、L3、L4と、を備える。【選択図】図2
