Abstract: Water mist generating head comprises a twin-flow body with water and gas manifolds, axially symmetrical gas nozzles and annular water port, concentrically situated between the nozzles. The water port has a water nozzle at the outlet, convergent towards the axis and gas nozzles, central and outer annular, having a Laval nozzle profile with outlet channel with walls parallel to the axis. The head is designed for the purpose of extinguishing fires and deactivation of chemical and biological contamination.