Gas Generator

A gas generator in which, between an ignition device and an inner cylindrical member, on a side of the lid wall portion, a transfer charge chamber is formed, and on a side of another end portion of a peripheral wall portion, a flow space is formed, the flow space being a space configured to allow combustion gas to flow in from the transfer charge chamber when an igniter is actuated, and being a space configured to allow the combustion gas to flow out to the outside of the inner cylindrical member when the igniter is actuated, and a total cross-sectional area of an inflow path serving a flow path through which the combustion gas flows from the transfer charge chamber into the flow space is configured to be smaller than a cross-sectional area of the flow space.