A gas generator includes, a housing provided with a gas discharge port, an ignition chamber, accommodating an igniter and a transfer charge, provided on an end portion of the housing, a combustion chamber disposed within the housing and accommodating a gas generating agent, a rupturable closing member partitioning the combustion chamber from the ignition chamber and including a rupturable portion ruptured upon an actuation of the gas generator, and an inner tube extending from the closing member toward the gas discharge port inside the combustion chamber. The inner tube defines outside thereof a space containing the gas generating agent, and defines inside a hollow space. The inner tube is provided with a plurality of through holes. The inner tube includes one end communicating the hollow space with the ignition chamber to transfer the transfer charge in a burning state toward an opposite end when the rupturable portion is ruptured.