An endoscope treatment tool includes: a sheath having a lumen； a basket portion being configured to protrude from the lumen and formed of at least one elastic wire； and a manipulation wire causing the basket portion to be moved, wherein the elastic wire has a maximum-outer-diameter portion between distal and proximal ends of the elastic wire and a largest portion that, between the maximum-outer-diameter portion and the proximal end of the elastic wire, reaches the maximum size in an opposite direction from maximum-outer-diameter portion in a side view from a direction orthogonal to a perpendicular line drawn to a center axis from the maximum-outer-diameter portion, and wherein, in a front view of the basket portion, the largest portion is positioned on an opposite side from the side of the maximum-outer-diameter portion with respect to a straight line that is orthogonal to the perpendicular line on the center axis.
