This treatment tool for biopsy includes a needle tube which is formed with a sharp distal end and is capable of piercing tissue, a first aperture which is provided in the distal end of the needle tube, a second aperture which is provided at more proximal end side than the first aperture, and communicates with an inner space in the needle tube. In a cross-section taken in a depth direction of the second aperture, each of a distal end side and a proximal end side of the second aperture is formed in a curved shape, and each of a proximal end part of the distal end side and a distal end part of the proximal end side make an acute angle with the axis of the needle tube.
