An instrument suitable for minimal invasive surgery. The instrument can be introduced into a body, for example, through a trocar, and has two arms and a centrally guided knife for clamping vessels. The central guidance of the knife in at least one of the arms avoids disadvantages that could otherwise develop as a result of the off-center severing of coagulated tissue. Moreover, the clean central guidance of the knife results in lower wear on the knife. Thus, a better cut quality and a longer service life of the knife can be achieved.