Surgical instrument

A surgical instrument comprising:

• an end tool including a first jaw and a second jaw that are rotatable;
• a manipulation part including an actuation manipulation part configured to control actuation motions of the first jaw and the second jaw, the manipulation part being configured to control motions of the end tool;
• a power transmission part comprising:
• a first jaw wire connected to the manipulation part to transfer a rotation of the manipulation part to the first jaw;
• and
• a second jaw wire connected to the manipulation part to transfer the rotation of the manipulation part to the second jaw,
• wherein the actuation manipulation part comprises:
• an actuation pulley rotatable around an actuation rotation shaft;
• and
• a handle member that is fixedly coupled to the actuation pulley, the handle member being rotatable along with the actuation pulley;
• and
• a tensioner configured to rotate along with the rotation of the actuation pulley,
• wherein the tensioner is configured to come into contact with the first jaw wire or the second jaw wire according to the rotation of the actuation pulley to apply additional tension to the first jaw wire or the second jaw wire.