An endoscope treatment tool includes a flexible sheath, a manipulation wire, and a basket portion constituted by a locking portion and a plurality of elastic wires. A maximum outside diameter portion of the basket portion is at a position closer to the locking portion than an intermediate position between a proximal end of the basket portion and the locking portion. The plurality of elastic wires is formed in a shape of a helix, and a winding pitch of the plurality of elastic wires becomes gradually smaller in a direction from a proximal side to the distal side of the manipulation wire. When a proximal side of the basket portion is reduced, an outside diameter of the maximum outside diameter portion is maintained at substantially a same size as the outside diameter before the proximal side of the basket portion is reduced.