Gas generator, in particular for use in airbag systems

Gas generator comprises at least one combustion chamber (2) with through openings (7) and a gas-producing charge (1), an expansion chamber (9), and an annular cooling chamber (10) protruding into the expansion chamber and arranged concentrically to the peripheral outer wall (23) of the combustion chamber. The cooling chamber has in its outer wall (12) at least one gas inlet opening (13) and at least one gas outlet opening (15) arranged outside the expansion chamber. The through openings of the combustion chamber are arranged so that reaction products exiting from the combustion chamber first enter a first annular space (24) of the expansion chamber surrounded by the cooling chamber. Preferred Features: The cooling chamber has at least one fine filter made of a metal, ceramic or a ceramic-metal composite. A coarse filter made of a metal, ceramic or a ceramic-metal composite is placed behind the fine filter in the direction of flow.