To provide a gas generator which sufficiently attains crush preventing function of a gas generating agent and is manufactured compact and inexpensively.

The disk type gas generator 100 includes: a housing including a combustion chamber 140 in which the gas generating agent 141 is housed; an igniter 130 attached to the housing and burning the gas generating agent 141 by being operated; and a cushion material 1A arranged in the combustion chamber 140 and preventing the crush of the gas generating agent 141. The sheet like cushion material 1A is constructed by a member containing one of an ethylene-propylene rubber and an ethylene-propylene-butadiene rubber as a main component.