Gas generator for an airbag

The gas generator has a sleeve-form housing (12) made of compression-resistant material and within which is located a propellant core (22) equipped with an enclosure (26). The propellant core has a circular cross section and the enclosure has a polygonal cross section. The sleeve-form housing is constructed from several layers. The housing has an inner layer (18) and outer layer (14) of plastic, and an aluminum middle layer (16) connected to the inner and outer layers. Alternatively, the outer layer may be plastic and the inner layer aluminum.