A vacuum die casting apparatus includes a casting cavity (10), which is evacuatable via a vacuum valve (26). A liquid casting material is pressable into the casting cavity by a piston (14) actuated by an actuator (17). A filling level sensor (20) detects a predetermined filling level of the casting material in the casting cavity. A control device (34) is connected to the filling level sensor for controlling the vacuum valve, and a position sensor (32) is connected to the control device (34) for detecting movement of the piston (14). The control device generates a closing signal for the vacuum valve (26) when the piston, after reaching the position (s₁) at which the filling level sensor (20) indicates a predetermined filling level of the casting cavity (10) with casting material has been reached, is displaced in a predetermined manner.