Method for producing fire fighting foam using a composition is prepared consisting of foaming agent, water and gaseous medium. The composition is prepared via dissolving or emulsifying the components in one another under overpressure, the composition prepared this way is stored under overpressure at the required place for the required period of time, transported if necessary maintaining the overpressure, and it is expanded via decompressing it on the spot and at the time of application. The apparatus for producing the fire fighting foam comprises a high-pressure foam source (10), a foam expanding spreading device (60) and a pressure resistant pipeline (40) connecting the high-pressure foam source (10) with the foam expanding spreading device (60). A foam expanding spreading device comprises an admission opening and a discharge mouth, a tubular distributing body (63) suitably forming a closed loop of tubes, preferably of torus shape, the discharge mouth, suitably a slit (65) or a set of holes, is situated on the nappe of the tube along its length, preferably along its generating line.