An endoscopic treatment tool includes: a tubular insertion part a stopper having a through hole and provided at a distal end part of the insertion part a manipulation wire inserted through the insertion part to be advanceable and retractable a knife part provided at a distal end part of the manipulation wire and inserted through the through hole and a restriction member provided closer to a proximal end side than the stopper and connecting the knife part and the manipulation wire. The stopper has an inner surface which is in surface contact with a part of the restriction member. When the restriction member is pressed against the stopper, the knife part is locked not to be rotated with respect to the insertion part, the restriction member and the stopper have a non-contact region at at least a part thereof in a direction about the axis of the insertion part, and the restriction member is in surface contact with the stopper such that the non-contact region is located entirely in an axial direction of the insertion part in a region at which the inner surface is disposed.
