A surgical instrument includes a shaft portion which at least partly houses an axially movable cutting element. A handle receives the shaft portion. A trigger element for the cutting element is movably arranged on the handle. The instrument also includes a coupling mechanism which converts a rotation of the trigger element into an axial movement of the cutting element with the interposition of a pinion. The coupling mechanism is designed such that the rotation of the trigger element produces a rotation of the pinion about the central axis thereof and additionally an axial movement of the central axis.
