Provided is a flexible mechanism. The flexible mechanism comprises: a flexible backbone which is introduced into a treatment area in the human body and which bends along a path in the human body; and a wire for transmitting an operation force provided through a handler prepared at one end of the flexible backbone to an end-effector prepared at the other end of the flexible backbone, wherein the wire extends from the one end of the flexible backbone to the other end of the flexible backbone and can wind around the outer circumferential surface of the flexible backbone in multiples of 360 degrees or passes through a spiral path formed on an inner surface in multiples of 360 degrees.