Abstract: The invention relates to a device for the production of foam by emulsion of a liquid substance (9) placed in a reservoir (1+2) consisting of a deformable resilient sealed container (1) and an end piece (2), wherein the device is hand-held and produces foam when a manual pressure is exerted to deform the container (1). The device according to the invention comprises a magazine (5) which includes two orifices (51,52) enabling exchanges of air and liquid substance between the reservoir and the magazine; a non-return valve (54) being associated with the second orifice, in such a way as to keep a quantity of liquid substance permanently in the magazine. The device according to the invention makes it possible to obtain a quality foam, in a very responsive manner and in a controlled quantity, quasi-independently of the force or of the period of the manual pressure. The dimensioning of the magazine (5) enables an optimal respiration of the reservoir between two manual presses.