A bone cement mixer includes one mixing space (5) for mixing powder and liquid components (2, 4) to make bone cement. The powder component (2) is placed in the mixing space (5) and the liquid component (4) in a liquid container (3). The liquid container (3) may be an aerosol container (15) and contains, in addition to the liquid component (4), a propellant gas for pushing the liquid component (4) out from the aerosol container (15) into the mixing space (5). The aerosol container (15) has a connecting element (16) for connecting it to the bone cement mixer (1), and it is closed and adapted to being opened when it is connected to a corresponding connecting element (17) on the bone cement mixer (1), so that the liquid component (4) is pushed out from the aerosol container (15) into the mixing space (5) by the propellant gas.