GAS GENERATOR

A gas generator includes an igniter assembly configured to release the combustion product and including an igniter body, the igniter body including an igniter cup ruptured by a combustion product and an electro-conductive pin that supplies a current, a collar portion holding the igniter body, and a holding portion interposed between the igniter body and the collar portion, a housing including a combustion chamber accommodating a gas generating agent, and including a gas discharge port through which a combustion gas is discharged, and an elastic member being disposed between the igniter assembly and the gas generating agent with an axial direction of the elastic member being in a direction same as a direction of the housing, the elastic member including a regulation portion at an inner periphery thereof, the regulation portion being configured to regulate a direction in which the igniter cup ruptured expands.