In the biopsy system according to one embodiment, the needle tube of the treatment tool has the minor axis of the flattened portion and the bending plane of the bending portion parallel to each other. Accordingly, the needle tube is easily bent in the bending direction of the bending portion, and even in an endoscope that has few bendable directions and is bendable, for example, in only two directions (e.g., up and down), the bending operation of the bending portion is not easily hindered. As a result, even after the treatment tool for endoscopes is inserted into the endoscope, the bending portion can be easily bent with a predetermined bending amount, and a procedure can be easily performed.