This medical treatment tool (1) includes: a treatment portion (10) having a first forceps piece (11) and a second forceps piece (12) that are coupled to each other so as to be relatively rotatable about a forceps rotating shaft (13) an operation member (20) at least a part of which has flexibility and a distal end of which is connected to a proximal end of the treatment portion (10) and a sheath portion (30) which has flexibility and through which the operation member (20) is inserted so as to be capable of advancing and retracting in a longitudinal direction of the sheath portion, wherein in the operation member (20), a range with a predetermined length from a distal end is a hard portion (20A) with rigidity higher than that of an other portion, a connecting portion between the treatment portion (10) and the operation member (20) is set so as to be located outside the sheath portion (30) in a state with the operation member (20) being retracted as much as possible, and the length of the hard portion (20A) is set so that the other portion is not exposed to an outside of the sheath portion (30) in a state with the operation member (20) being advanced as much as possible.
