A device for producing a bone cement paste from a monomer liquid and a cement powder as starting components of the bone cement paste and for discharging the mixed bone cement paste, the device having: a cartridge (1, 101) comprising a cylindrical interior, wherein a discharging plunger (7, 107), which can move towards a front side of the cartridge (1, 101), is arranged in the interior of the cartridge (1, 101) in a rear side of the cartridge (1, 101), a receptacle (2, 102), which extends along a longitudinal direction, wherein a front side of the receptacle (2, 102) is connected to the rear side of the cartridge (1, 101), a delivery plunger (6, 106), which is arranged in the receptacle (2, 102), wherein the delivery plunger (6, 106) is supported in the receptacle (2, 102) so that it can move in the longitudinal direction of the receptacle (2, 102) towards the front side of the receptacle (2, 102), a breakable ampoule containing the monomer liquid, wherein the ampoule is arranged in the receptacle (2, 102) between the delivery plunger (6, 106) and the discharging plunger (7, 107), and wherein the ampoule has an ampoule body, wherein the ampoule body at least partially abuts on the inner wall of the receptacle (2, 102), and a spacer (9, 109), which is arranged in the receptacle (2, 102) between the discharging plunger (7, 107) and the ampoule body or between the delivery plunger (6, 106) and the ampoule body, wherein the spacer (9, 109) extends in the longitudinal direction of the receptacle (2, 102) and characterised in that the spacer (9, 109) is spaced apart from the inner wall of the receptacle (2, 102) at a distance, which is at least as large as the wall thickness of the ampoule body. a cartridge (1, 101) comprising a cylindrical interior, wherein a discharging plunger (7, 107), which can move towards a front side of the cartridge (1, 101), is arranged in the interior of the cartridge (1, 101) in a rear side of the cartridge (1, 101), a receptacle (2, 102), which extends along a longitudinal direction, wherein a front side of the receptacle (2, 102) is connected to the rear side of the cartridge (1, 101), a delivery plunger (6, 106), which is arranged in the receptacle (2, 102), wherein the delivery plunger (6, 106) is supported in the receptacle (2, 102) so that it can move in the longitudinal direction of the receptacle (2, 102) towards the front side of the receptacle (2, 102), a breakable ampoule containing the monomer liquid, wherein the ampoule is arranged in the receptacle (2, 102) between the delivery plunger (6, 106) and the discharging plunger (7, 107), and wherein the ampoule has an ampoule body, wherein the ampoule body at least partially abuts on the inner wall of the receptacle (2, 102), and a spacer (9, 109), which is arranged in the receptacle (2, 102) between the discharging plunger (7, 107) and the ampoule body or between the delivery plunger (6, 106) and the ampoule body, wherein the spacer (9, 109) extends in the longitudinal direction of the receptacle (2, 102) and characterised in that the spacer (9, 109) is spaced apart from the inner wall of the receptacle (2, 102) at a distance, which is at least as large as the wall thickness of the ampoule body.