GAS GENERATOR

Obtained is a gas generator that can control a size of rupture of a cup body to be stabilized while increasing a mechanical strength of the cup body. [0002] A gas generator includes a housing having a short cylindrical shape and accommodating a gas generating agent inside, an igniter including an ignition portion that accommodates an ignition charge, and a cup-shaped member including an enhancer chamber that accommodates an enhance agent inside and including a single bottomed cylindrical member, in which a thin weak member is disposed on a part of a top wall portion of the cup-shaped member, a side wall portion of the cup-shaped member having a mechanical strength higher than a mechanical strength of the weak member is provided, the side wall portion of the cup-shaped member includes a thin portion provided close to the top wall portion, and a thick portion extending from the thin portion to a side opposite to the top wall portion along an axial direction, the weak member has a mechanical strength to rupture the cup-shaped member prior to the side wall portion in accordance with activation of the igniter, and the thin portion has a mechanical strength to rupture, deform, or melt when rupture in the weak member progresses to the thin portion.