PROBLEM TO BE SOLVED: To provide an ultrasonic endoscope and an insertion assistance tool which can be quickly inserted into a body to be examined thanks to the improved insertability of an insertion portion of the ultrasonic endoscope.SOLUTION: The ultrasonic endoscope has: the insertion portion a treatment tool insertion opening which is an opening provided at the tip of the insertion portion and provided capably of projecting the treatment tool along the insertion shaft of the tip an ultrasonic wave observation portion having an ultrasonic vibrator to send and receive ultrasonic waves, and an ultrasonic vibrator to send and receive ultrasonic waves, projecting in the tip direction from the treatment tool insertion opening and arranged to allow the plane including the scanning plane of the ultrasonic waves to pass through the treatment tool insertion opening and a slope portion formed of a surface sloping with respect to the insertion axis so as to separate more from the ultrasonic wave observation portion toward the base end side from the region contacting or intersecting the part of the surface of the ultrasonic wave observation portion that faces the treatment tool insertion opening and contacting or intersecting the surface of the ultrasonic wave observation portion when viewed from the direction orthogonal to the scanning plane.COPYRIGHT: (C)2012,JPO&INPIT【課題】本発明は、超音波内視鏡の挿入部の挿入性を向上させ速やかに被検体内に挿入することができる超音波内視鏡及び挿入補助具を提供する。【解決手段】本発明の超音波内視鏡は、挿入部と、前記挿入部の先端部に設けられた開口部であって、処置具を前記先端部の挿入軸に沿って突出可能に設けられた処置具挿通口と、超音波を送受するための超音波振動子を有してなり、前記処置具挿通口よりも先端方向に突出し、前記超音波の走査面を含む平面が前記処置具挿通口を通過するように配設された超音波観察部と、前記走査面に直交する方向から見た場合に、前記超音波観察部の表面のうちの前記処置具挿通口に面した表面に接する又は交わり、かつ前記超音波観察部の表面と接する又は交わる部位から基端側に向かうにつれて、前記超音波観察部から離れるように前記挿入軸に対して傾斜した面からなる斜面部と、を具備する。【選択図】図2
