A surgical instrument in HF design includes two tissue branches, at least one of the tissue branches being movable relative to the other tissue branch and being able to be applied to the other tissue branch with a predetermined or predeterminable contact pressure via an actuation mechanism while clamping body tissue between the tissue branches. A clamping pressure controlling or adjustment device is interconnected in a force or torque gear train between the actuation mechanism and the at least one movable tissue branch.