A vacuum mixing system for the mixing of polymethylmethacrylate bone cement comprising at least one cartridge (4) having an evacuatable internal space (5) for the mixing of the bone cement, the internal space (5) of which comprises a cylindrical swept volume, a mixing element (12) that is arranged in the internal space (5) of the cartridge (4) such as to be mobile and can be operated from outside the vacuum mixing system in order to mix the content in the internal space (5) of the cartridge (4), and a dispensing plunger (2) having a cylindrical external circumference whose first base surface borders a base surface of the internal space (5) of the cartridge (4) and which can be or is locked to the cartridge (4) in detachable manner and which, in the detached state, is mobile in the cylindrical region of the internal space (5) of the cartridge (4).