The utility model relates to a gas-type gas generator. An ignition chamber, a combustion chamber and a filter chamber are arranged in a main body consisting of an upper shell and a lower shell; the inner shell is installed on the inner wall of the lower shell; an electric detonator is installed on a central hole of the lower shell; the ignition shell is installed in the lower shell to form the ignition chamber; automatic ignition powder is stored in the ignition chamber; a combustion chamber cover is installed on the upper end of the inner shell; the outer side wall of the combustion chamber cover is embedded into the inner wall of the inner shell; a filter net is arranged on the combustion chamber cover; a filter chamber cover is installed in an inner hole of the filter net; the top of the ignition shell stretches out of the central hole of the combustion chamber cover to push against the inner bottom surface of the filter chamber; a gas-generation agent is stored in the combustion chamber; a fire transfer hole is formed in the outer wall of the ignition shell; an exhaust passage is formed between the combustion chamber and the filter chamber; an annular airflow passage is formed between the inner wall of the upper shell and the outer wall of the inner shell, and an exhaust hole is formed in a position, corresponding to the annular airflow passage, of the annular circumferential surface of the upper shell; the inner side of the exhaust hole is provided with a sealing foil in an adhesion manner. By adopting the gas-type gas generator, the ignition reliability can be effectively improved, the size of an ignition system can be reduced, and the miniaturization and light weight of the generator can be facilitated.