An endoscope treatment tool (1, 2, 3, 4) comprising: a sheath; a support part which is attached to a distal end portion of the sheath; forceps members (12, 13) which are arranged at the distal end of the sheath, wherein the forceps members (12, 13) are supported so as to be pivotable around a pivot shaft provided at the support part, and have a pair of opposed surfaces (12a, 13a); an operating wire which is inserted through the sheath so as to be capable of advancing into and retracting from the sheath, wherein the operating wire brings the pair of opposed surfaces (12a, 13a) closer to each other at a position closer to a distal end side from the pivot shaft as the operating wire is separated from the pivot shaft, and separates the pair of opposed surfaces (12a, 13a) from each other as the operating wire approaches the pivot shaft; an elastic member (35; 51; 62) which is supported by the operating wire or the support part; and a stopper (33; 12b, 13b) which is provided on the operating wire or the forceps members (12, 13), wherein the stopper (33; 12b, 13b) is separated from the elastic member (35; 51; 62) which is in a natural state when the pair of the opposed surfaces (12a, 13a) abut against each other, wherein the stopper (33; 12b, 13b) moves to a contact position where the stopper (33; 12b, 13b) comes into contact with the elastic member (35; 51; 62) which is in the natural state when the operating wire approaches the pivot shaft to thereby move the pair of the opposed surfaces (12a, 12b) away from each other, and wherein, when the stopper (33; 12b, 13b) positioned at the contact position is further moved forward by moving the operating wire toward the pivot shaft, the elastic member (35; 51; 62) is elastically deformed by the stopper (33; 12b, 13b), and the pair of opposed surfaces (12a, 13a) further moves away from each other. a sheath; a support part which is attached to a distal end portion of the sheath; forceps members (12, 13) which are arranged at the distal end of the sheath, wherein the forceps members (12, 13) are supported so as to be pivotable around a pivot shaft provided at the support part, and have a pair of opposed surfaces (12a, 13a); an operating wire which is inserted through the sheath so as to be capable of advancing into and retracting from the sheath, wherein the operating wire brings the pair of opposed surfaces (12a, 13a) closer to each other at a position closer to a distal end side from the pivot shaft as the operating wire is separated from the pivot shaft, and separates the pair of opposed surfaces (12a, 13a) from each other as the operating wire approaches the pivot shaft; an elastic member (35; 51; 62) which is supported by the operating wire or the support part; and a stopper (33; 12b, 13b) which is provided on the operating wire or the forceps members (12, 13), wherein the stopper (33; 12b, 13b) is separated from the elastic member (35; 51; 62) which is in a natural state when the pair of the opposed surfaces (12a, 13a) abut against each other, wherein the stopper (33; 12b, 13b) moves to a contact position where the stopper (33; 12b, 13b) comes into contact with the elastic member (35; 51; 62) which is in the natural state when the operating wire approaches the pivot shaft to thereby move the pair of the opposed surfaces (12a, 12b) away from each other, and wherein, when the stopper (33; 12b, 13b) positioned at the contact position is further moved forward by moving the operating wire toward the pivot shaft, the elastic member (35; 51; 62) is elastically deformed by the stopper (33; 12b, 13b), and the pair of opposed surfaces (12a, 13a) further moves away from each other.