The curved portion is always disposed within the projection plane of the probe body portion when the probe body portion is viewed from the proximal end toward the distal end along the longitudinal axis. Wherein the curved portion includes a first bent surface which is bent with respect to the circumferential surface of the probe main body so as to come into contact with the longitudinal axis while approaching the longitudinal axis and a second bent surface which is bent from the longitudinal axis of the first bent surface The second bent surface bent with respect to the first bent surface in a direction away from the first bent surface and the second bent surface bent with respect to the second bent surface in a direction approaching the longitudinal axis opposite to the bent direction of the first bent surface And the third bent surface extending toward an extension line of the first bent surface. Wherein the curved portion includes a first treatment surface which is bent in the bending direction of the first bent surface with respect to the third bent surface and a second treatment surface which is located on the extension line or is bounded by the extension line as a boundary And a treatment site located on the opposite side of the treatment site.前記湾曲部は、前記長手軸に沿って前記基端から前記先端に向かって前記プローブ本体部をみたときに、前記プローブ本体部の投影面内に常に配置される。前記湾曲部は、前記長手軸に近づいて前記長手軸上に接するように前記プローブ本体部の周面に対して折れ曲がる第1折曲面と、前記第1折曲面の折曲方向且つ前記長手軸から離れる方向に向かって前記第1折曲面に対して折れ曲がる前記第2折曲面と、前記第1折曲面の折曲方向とは逆側である前記長手軸に近づく方向に向かって前記第2折曲面に対して折れ曲がり、前記第1折曲面の延長線に向かって延びる前記第3折曲面とを有する。前記湾曲部は、前記第3折曲面に対して前記第1折曲面の折曲方向に折れ曲がる第1処置面と、前記延長線上に位置する、または前記延長線を境界として前記長手軸とは境界を挟んで反対側に位置する処置部位とを有する。
