Abstract: Placed in a box (1) is a ceramic shell (21) delimiting a casting space (22), the shell being surrounded by a mass of binder-free sand (23). The casting space is connected to a source (4) of liquid metal located underneath, in which are applied, in succession, a pressure (P1) bringing the liquid to the threshold of the casting space (22), a pressure (P2) slightly greater than that necessary for filling this space, and then a marked overpressure (P3); finally, the pressure is brought back down to the first value (P1). When the casting space has been filled, an underpressure is created in the space containing the mass of sand (23) in order to prevent any deformation of the shell (21) due to the overpressure (P3), at least until the formation of a metal skin against the shell and at most until the start of the reduction in the overpressure in the source (4) of liquid metal.