The invention relates to a vacuum mixing device for mixing PMMA bone cementfrom amonomer liquid and a cement powder (9), the vacuum mixing device comprising atleastone cartridge (6) comprising an evacuable interior for mixing of the bonecement (96), amixing device (10) for mixing the content in the interior of the at least onecartridge (6),which is arranged movably in the interior, a receptacle (2) for receiving aseparatecontainer (54) containing the monomer liquid or comprising an integratedcontainercontaining the monomer liquid, an opening device (5), which is arranged in theregion ofthe receptacle (2) in a manner movable relative to the receptacle (2) so that,by movingthe opening device (5), a separate container (54) arranged in the receptacle(2) isopenable by means of the opening device (5), or the opening device (5) isarranged inthe region of the integrated container in a manner movable relative to theintegratedcontainer so that, by moving the opening device (5), the integrated containerisopenable by means of the opening device (5), a pump (3), in which a movableplunger(30) for generating a negative pressure is arranged and delimits a pumpchamber (94)of the pump (3), and a connection line (26), which connects the interior ofthe at leastone cartridge (6) to the pump chamber (94) of the pump (3), wherein the vacuummixingsystem comprises an operating element (4) that is operatable from outside,wherein theplunger (30) in the pump (3) is movable manually by means of the operatingelement(4), and wherein the opening device (5) is movable relative to the receptacle(2) orrelative to the integrated container by means of the same operating element(4), and themixing device (10) in the interior of the cartridge (6) is movable by means ofthe sameoperating element (4) in order to mix the content in the interior of thecartridge (6).The invention also relates to a method for mixing PMMA
