A treatment tool for an endoscope (1) which is transendoscopically inserted into a body cavity for use, and which includes: a sheath (10) at least partially composed of compound material in which thermoplastic resin and a crosslinking promoter are mixed； a manipulation wire inserted through the aforementioned sheath so as to be capable of advancing and retracting； a treatment part (20) attached to a first end of the aforementioned manipulation wire； and a manipulation part (30) attached to a second end of the aforementioned manipulation wire； wherein said sheath has a crosslinked part (11) where said thermoplastic resin is crosslinked by irradiating said compound material with ionizing radiation, and a non-crosslinked region (12) where said thermoplastic resin is not crosslinked.
