Abstract: There is described a device for preparing food products from cereals which have been pressure-cooked and thereafter expanded, which comprises a mould comprised of a hollow heated die to which the cereals are fed, a punch cooperating with said mould to close and open the cavity thereof by sliding, at least one jack so connected to the punch as to drive same alternately in and out of the mould cavity, said jack enabling to exert through the punch a pressure on the mould while cooking the cereals, stop means for stopping temporarily the alternating movement of the punch or of a driving member therefor in a position where said punch does not exert a pressure any more on the mould and where the mould cavity is not yet open, a device for feeding cereals to be cooked and a device for discharging the product from expanded cereals thus obtained.