An assisting tool for assisting the movement of the treatment instrument having the insert inserted into the channel of the endoscope with respect to the channel forms an insertion path through which the treatment instrument is inserted and from the other part of its entire length A flexible portion including a structure that is easily deformable and having an adjustable length that can adjust the overall length and a flexible portion that is provided in the flexible portion and connectable to the endoscope so as to communicate the channel and the insertion passage A flexible portion which is provided on the flexible portion and in which the length of the entire length is adjusted by the extendable portion among the operation portion connected to the insertion portion of the endoscope or the insertion portion, And a holding unit that holds a portion that can be reached.内視鏡のチャンネルに対して挿通される挿入体を有する処置具の、前記チャンネルに対する移動を補助する補助具は、前記処置具を挿通する挿通路を形成し、その全長のうち他の部位よりも変形し易い構造を含み前記全長を調整可能な伸縮部を有する、可撓部と、前記可撓部に設けられ、前記チャンネルと前記挿通路とを連通させるように前記内視鏡に連結可能な連結部と、前記可撓部に設けられ、前記内視鏡の挿入部又は前記挿入部に接続された操作部のうち、前記伸縮部により前記全長の長さが調整された前記可撓部が到達可能な部位を保持する保持部とを備える。
