Device for the production of foam comprising: - a reservoir for the supply of foaming liquid, of variable capacity, - a liquid chamber communicating with the foaming liquid supply reservoir by an inlet opening , and with a mixing chamber by a liquid outlet opening , - a first non-return valve disposed at the inlet opening of the liquid chamber , - a second non-return sealing valve (411, 412; 416) disposed at the liquid outlet opening , enabling a flow leaving the liquid chamber and comprising elastic means (415, 413; 417) for holding in the closed position, - an air chamber , - compression means for compressing the air chamber and the liquid chamber in order to expel liquid and air, via the liquid outlet opening and via the air outlet opening , into the mixing chamber which comprises stirring means for producing the foam discharged towards an outlet orifice , - a return means which returns the air chamber and the liquid chamber to their uncompressed position in order to produce suction of air and liquid, the return means is a deformable elastic bell-shaped component with a smooth wall which separates the liquid chamber and the air chamber hermetically by sealing means , characterised in that the liquid chamber corresponds to the space under the bell-shaped return means , the liquid outlet opening being formed at the top of the bell, the inlet opening of the liquid chamber being formed on a surface , at the base of the bell, separating the reservoir from at least the liquid chamber, and in that the foaming liquid supply reservoir of variable capacity comprises a movable piston which slides in sealing fashion against an inner wall of the reservoir, the movable piston being disposed opposite the inlet opening of the liquid chamber . - a reservoir for the supply of foaming liquid, of variable capacity, - a liquid chamber communicating with the foaming liquid supply reservoir by an inlet opening , and with a mixing chamber by a liquid outlet opening , - a first non-return valve disposed at the inlet opening of the liquid chamber , - a second non-return sealing valve (411, 412; 416) disposed at the liquid outlet opening , enabling a flow leaving the liquid chamber and comprising elastic means (415, 413; 417) for holding in the closed position, - an air chamber , - compression means for compressing the air chamber and the liquid chamber in order to expel liquid and air, via the liquid outlet opening and via the air outlet opening , into the mixing chamber which comprises stirring means for producing the foam discharged towards an outlet orifice , - a return means which returns the air chamber and the liquid chamber to their uncompressed position in order to produce suction of air and liquid, the return means is a deformable elastic bell-shaped component with a smooth wall which separates the liquid chamber and the air chamber hermetically by sealing means , characterised in that the liquid chamber corresponds to the space under the bell-shaped return means , the liquid outlet opening being formed at the top of the bell, the inlet opening of the liquid chamber being formed on a surface , at the base of the bell, separating the reservoir from at least the liquid chamber, and in that the foaming liquid supply reservoir of variable capacity comprises a movable piston which slides in sealing fashion against an inner wall of the reservoir, the movable piston being disposed opposite the inlet opening of the liquid chamber . <EOS>