A bone cement mixer (1) includes at least 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 component (4) is sucked out from the liquid container (3) to the mixing space (5) by means of a vacuum generated in the mixing space. The liquid container (3) is a tube (15) that has a connecting element (16) for connecting it to the bone cement mixer (1). The connecting element (16) is adapted to be opened when it is connected to a corresponding connecting element (17) on the bone cement mixer (1). The metal material of the tube has a thickness such that the volume of its liquid containing space (18) is brought to decrease when the vacuum in the mixing space (5) is brought to prevail therein.