Abstract: A gas generator, especially for a vehicle safety system, has a pyrotechnical igniter unit (22) and a holder (14) for the igniter unit (22). The igniter unit (22) is attached to the holder (14) in that the igniter unit (22) and the holder (14) are encapsulated together by one of injection molding and foaming of a plastic. The holder (14) has at least one passage opening (30, 38) for the plastic during the encapsulation by one of injection molding and foaming, the at least one opening being configured in such a way as to create a form-fitting anti-twist protection between the plastic (34) and the holder (14).