A surgical tool includes a longitudinal member a bending double joint that is coupled to the longitudinal member forceps pieces that are coupled to the bending double joint an opening and closing joint that is coupled to the forceps pieces and an opening and closing rod that is coupled to the opening and closing joint. The bending double joint has a first bending rotary shaft that is coupled to the longitudinal member and a second bending rotary shaft that is parallel to the first bending rotary shaft and is coupled to a treatment part. The opening and closing joint has a first gear that is coupled to the opening and closing rod and is rotated around a predetermined rotation center a second gear that is coupled to the first gear so as to relatively rotate in a direction opposite to the first gear coaxially with the second bending rotary shaft and a link that converts a rotational force of the second gear into the operation of the forceps pieces.
