A gas generator comprises an outflow chamber and a freeing element. The outflow chamber contains at least briefly gas under pressure, when the gas generator is activated and at least one outflow opening is arranged in a side wall of the outflow chamber. The freeing element is arranged non-displaceably in the outflow chamber and has a peripheral wall and a base wall. The peripheral wall extends along the side wall and closes at least one outflow opening before an activation of the gas generator. The base wall is connected with the peripheral wall. The freeing element is constructed so that on exceeding a predetermined gas pressure in the outflow chamber, the base wall turns inwards under partial plastic deformation of the peripheral wall and at least one hitherto concealed outflow opening is freed by the plastic deformation of the peripheral wall.