To provide a gas generator which has considerably improved seal reliability although the gas generator has a simple constitution and which attains the combustion performance having the variance smaller than that of the conventional gas generator and to provide a method for manufacturing the gas generator.

The gas generator includes a short cylindrical housing 10 comprising a lower cover 10b and an upper cover 10a for closing the lower cover. An ignition means 20 having an igniter 21 and an ignition agent 23 on the inside thereof, a gas generating agent 30 and a filter medium 40 are arranged in the housing 10 in this order from the center thereof. A cap-shaped clogging member 50 for sticking fast to an inner wall of a closure shell to clog a gas spout 12 is also arranged in the housing and a pressing cover 70 is arranged below the clogging member 50. A ringed ring member 60 is arranged on the inner wall of the closure shell. The edge of the clogging member 50 is joined/fixed to both of the upper cover 10a and the lower cover 10b by welding or the like.