Instrument for surgical assistance robot

An instrument for a surgical assistance robot, comprising:

• a main body;
• a shaft being a rod-shaped member extended from the main body;
• an end effector for surgical operation provided at a front end of the shaft in an axial direction;
• and
• a joint function part provided at the front end to bend with respect to the axial direction of the shaft, thereby to enable an orientation of the end effector to be changed, wherein
• the joint function part has a bending structure that enables the bending, and
• the bending structure comprises:
• an outer coiled part formed of a wire which is wound in a coiled shape to have a plurality of coils in the axial direction;
• and
• an inner coiled part formed of a wire which is wound in a coiled shape to have a plurality of coils in the axial direction and arranged in the outer coiled part, wherein
• the outer coiled part has a plurality of gaps to distance adjacent coils in the axial direction, and
• the coils of the inner coiled part are provided so as to correspond to the gaps of the outer coiled part and fit between the adjacent coils while being in contact with the adjacent coils of the outer coiled part.