This treatment tool for treating biological tissue comprises: first and second gripping parts each having a longitudinal axis and each having a gripping surface, the gripping surfaces being capable of gripping biological tissue therebetween by opening and closing in an opening/closing direction that is orthogonal to or substantially orthogonal to the longitudinal axis； a rotating body that includes an operating part having an edge part capable of cutting biological tissue by rotating about a central axis that matches or is substantially parallel to the longitudinal axis, the rotating body being capable of moving the edge part from the first gripping part toward the second gripping part； a first guiding part that is provided to the first gripping part, and that is capable of guiding the edge part toward the second gripping part through the gripping surface of the first gripping part； and a second guiding part that is provided to the second gripping part, and that is capable of guiding the edge part to the second gripping part through the gripping surface of the first gripping part so as to enable the cutting of the biological tissue at the time of guiding the edge part to the second gripping part through the gripping surface of the first gripping part.L'invention concerne un outil de traitement destiné à traiter un tissu biologique, comprenant : des première et seconde parties de préhension ayant chacune un axe longitudinal et ayant chacune une surface de préhension, les surfaces de préhension étant capables de saisir le tissu biologique entre elles par une ouverture et une fermeture dans une direction d'ouverture/fermeture qui est orthogonale ou sensiblement orthogonale à l'axe longitudinal； un corps rotatif qui inclut un partie fonctionnelle ayant une partie de bord capable de couper le tissu biologique en tournant autour d'un axe central qui correspond ou est sensiblement parallèle à l'axe longitudinal, le corps rotatif étant capable de déplacer la partie de bord
