The endoscopic treatment instrument (1), first sheath operation wire that is movable forward and backward operable has the distal end treatment portion (2) and (3), the operation wire (3) is inserted (4) and, which is provided a second sheath that the first sheath (4) is inserted, the treatment section (2) protrudes from the tip (5), the treatment section (2), with the advancing and retracting operation manipulation wire (3) second stopper for limiting the first stopper locking portion that moves forward and backward (12), to restrict the forward movement of the locking portion (12) and (17), the rearward movement of the locking portion (12) and (20), I and a sheath operating section for advancing and retracting, and a second position in relation to the first positional relationship relative position in the axial direction with respect to (4) first sheath are different from each other, the second sheath (5).この内視鏡用処置具(1)は、処置部(2)を先端に有し進退操作可能とされた操作ワイヤ(3)と、操作ワイヤ(3)が挿通された第1シース(4)と、第1シース(4)が挿入され、先端から処置部(2)が突出する第2シース(5)と、処置部(2)に設けられ、操作ワイヤ(3)の進退操作に伴って進退する係止部(12)と、係止部(12)の前進移動を規制する第1ストッパ(17)と、係止部(12)の後退移動を規制する第2ストッパ(20)と、第2シース(5)を、第1シース(4)に対する軸線方向の相対位置が互いに異なる第1位置関係と第2位置関係との間で進退させるシース操作部とを備える。
