The invention relates to a surgical instrument comprising an instrument handle linked to a proximal end portion of a tube shaft to the distal end portion of which an instrument head is linked so as to be bendable, in which instrument head an effector including at least one pivotal engaging element is rotatably supported. The instrument handle has a number of manipulators and/or operating mechanisms for operating the instrument head and/or the effector via gear trains. According to the invention, a clutch which permits a zero point adjustment individual at least over a predetermined pivoting range of the instrument handle is interposed in the gear train effecting the bending motion of the instrument head. The zero point is defined as a relative position of the instrument handle with respect to the tube shaft in which the instrument head adopts a predetermined bending position with respect to the tube shaft.