The distal cover (23) of the calculus breaking device (1), which is an endoscope treatment tool, includes a first opening (23a) opened toward the coil sheath (20), a first opening (23a), and Is a second opening (23b) opened toward the opposite side, a passage (24) connecting the first opening (23a) and the second opening (23b), and a first opening (23a). And a wall of the tip cover (23) in a cross section including an inner peripheral surface (25) provided in the passage portion (24) and capable of contacting the elastic wire (7) and a center line (X1) of the tip cover (23). An elastic wire (7) provided in the passage portion (24) so as to bend and have a radius of curvature (R0) larger than the thickness dimension (t) and connect the inner peripheral surface (25) and the second opening portion (23b). And a slidable curved surface (26).内視鏡用処置具である結石破砕装置（１）の先端カバー（２３）は、コイルシース（２０）側に向けて開口された第一開口部（２３ａ）と、第一開口部（２３ａ）とは反対側に向けて開口された第二開口部（２３ｂ）と、第一開口部（２３ａ）と第二開口部（２３ｂ）とを繋ぐ通路部（２４）と、第一開口部（２３ａ）に繋がって通路部（２４）に設けられ弾性ワイヤ（７）に接触可能な内周面（２５）と、先端カバー（２３）の中心線（Ｘ１）を含む断面において先端カバー（２３）の肉厚寸法（ｔ）よりも大きな曲率半径（Ｒ０）を有して湾曲し内周面（２５）と第二開口部（２３ｂ）とを繋ぐように通路部（２４）に設けられ弾性ワイヤ（７）が摺動可能な湾曲面（２６）と、を有する。
