The liquid transfer tool to be mounted on the treatment instrument includes a main pipe arranged along the elongated member of the treatment tool whose longitudinal axis is defined and capable of allowing a liquid to flow around the outer periphery of the elongated member, A connecting portion which is disposed on the proximal side along the longitudinal axis and connects the interior of the main conduit and the interior of the liquid sending channel from the liquid source, a connecting portion disposed in the connecting portion and having a proximal end of the elongated member And a fixing portion for fixing the connecting portion to a handle unit to be gripped by a user.処置具に装着される送液具は、長手軸が規定される処置具の長尺部材に沿って配置され前記長尺部材の外周に液体を流すことが可能な主管路と、前記主管路のうち前記長手軸に沿って基端側に配置され前記主管路の内部と液体源からの送液路の内部とを連結する連結部と、前記連結部に配置され、前記長尺部材の基端に配置されユーザに把持されるハンドルユニットに対して前記連結部を固定させる固定部とを有する。
