The present invention, in the conventional housing, the first end side from this order, and the gas inlet chamber and the pressure gas chamber having an ignition means chamber, the gas discharge port is disposed, with a between the pressurized gas chamber and the gas inlet chamber, fixed to the annular fixing and it is closed by rupture disc, the ignition means chamber and the breaking means of the rupture disc between the gas inlet chamber is arranged, that the destruction unit, the base part and the rod main body portion and the distal end extends toward the rupture disk from the base part have extended parts of diameter , in operation, the movement of a base portion axially, and adding the increased diameter located within the pressurized gas chamber after punching the rupture disc, and add the rod main body of the cyclic and the position opposite to the government and the radial direction, the compressed gas is, the increased diameter portion and the annular and the first annular passage and the width between the state change, and the rod body portion wherein Phase and the second after passing through the gas passage comprises an annular passage, and discharged from the gas discharge port, wherein the second cross-sectional area of ​​the annular passage, the first area and the gas of the minimum width portion of the annular passageway outlet between government and the minimum of the total opening area, when the second area of ​​the cross sectional area of ​​the annular passage Q, punching rupture disc A1, the area of ​​the minimum width portion of the first annular passage A2, the Q <(A2-A1) a gas generator for satisfied.