The invention relates to a device for forming aerosol, the device comprising at least one gas-dispersing atomizer for atomizing a liquid into aerosol by means of gas at an atomizing head of the atomizer and an atomizing chamber, which is in flow connection with the atomizing head and in which flow restraints are arranged for changing the hydrodynamic properties of the aerosol flow discharging from the atomizing head. According to the present invention the flow restraints are arranged in the inner walls of the atomizing chamber in such a manner that they protrude from the inner walls to the inside of the atomizing chamber.