A surgical instrument with a parallel gripping and clamping vascular clamp, which is equipped with coupling elements which makes possible a combination of a known detachable operating arrangement and of an actuating tool, in order to keep the access opening in the thorax free of intrusive instruments. With the parallel gripping and clamping operating means of the inventive vascular clamp, the known scissor-like means are dispensed with, and a parallel adjustment of the operating means takes place by means of a lever gear according to the invention. The lever gear is formed from a stationary lever, constructed as a body element, and from several movable levers, consisting of the tension- and pressure element, a push-pull rod, two toggle levers, two pivot arms and two movable branches. The lever gear has nine axes and converts a linear drive movement for adjusting the operating means into a rotationally movable one, whereby the two movable branches are displaceable substantially in a parallel manner towards one another and away from one another.