A treatment device for an endoscope (1) includes an operating wire (3) having a treatment section (2) at a distal end thereof , a first sheath (4) through which the operating wire (3) is inserted, a second sheath (5) into which the first sheath (4) is inserted and from a distal end of which the treatment section (2) protrudes, a locking portion (12) provided in the treatment section (2) to advance or retreat in the direction of the axis with advance or retreat operation of the operating wire (3), a first stopper (17) that regulates advance movement of the locking portion (12), a second stopper (20) that regulates retreat movement of the locking portion (12), and a sheath operating portion that advances or retreats the second sheath (5) between a first positional relationship and a second positional relationship where relative positions with respect to the first sheath (4) along a direction of axis are mutually different.
