The invention relates to a blood vessel sealing device comprising a clamp which has a pair of jaws that can move relative to each other for inserting and crimping a blood vessel, said jaws containing high-frequency (HF) jaw electrodes (12a, 12b), and comprising an electrical HF power supply circuit (8) including an HF generator (10) and the HF jaw electrodes.The blood vessel sealing device according to the invention further comprises an impedance control device (9) for continuously measuring and maintaining constant the impedance of the HF power supply circuit in the course of the respective sealing operation. For this purpose, the HF generator includes a variable impedance HF resonant circuit with a capacitor unit (13) and a coil unit (14), and comprising the jaw electrodes, wherein the inductance of the coil unit and/or the ohmic resistance of the HF resonant circuit is/are variably adjustable and/or wherein the capacitance of the capacitor unit is variably adjustable and the capacitor unit comprises an electrically controllable capacitance diode or at least one movable capacitance-altering capacitor electrode arranged in the clamp.A blood vessel sealing device of this type can be used, for example, for sealing of vessels for blood donation bags.
