Abstract: In a process by which a distal end support member of an endoscopic treatment tool that has a drive mechanism holding groove portion and a sheath coupling portion is fabricated, a drive mechanism holding groove portion is formed by forging that portion of a cylindrical metal stock which is closer to its front end such that it is extruded along the longitudinal axis to form a slit of gap in the middle while the sheath coupling portion is formed by forging that portion of the metal stock which is closer to its rear end such that it is extruded in an annular shape in a direction opposite the first direction of extrusion.