An endoscope treatment tool includes a sheath having electric insulation and an electrode unit provided at a distal end portion of the sheath. The electrode unit includes a rod-shaped electrode that is provided to extend in an axis direction of the sheath and is capable of being arranged in a state where the electrode protrudes from the distal end portion of the sheath and is exposed to the outside and a chip that is fixed in a state where a distal end portion of the electrode is inserted into a concave portion provided in a proximal end surface so as to extend in the axis direction, has a greater external diameter than the external diameter of the electrode, and is formed from a single electric insulation material. The concave portion is formed with a smaller-diameter portion that allows the distal end portion of the electrode to be inserted thereinto and has a smaller internal diameter than the internal diameter of the concave portion. A filling member capable of being engaged to the smaller-diameter portion is provided further toward a distal end side than the smaller-diameter portion between the concave portion and the electrode.
