Provided is a gas generating composition that maintains stable ignition performance for a long period. A gas generating composition includes: a gas generating agent including (a) fuel selected from a triazine compound and a guanidine compound, (b) an oxidizing agent including a Combination of (b-1) basic metal nitrate and (b-2) basic metal carbonate, and (c) a binder; and (d) an absorbent. The gas generating agent and the absorbent may not be integrally molded or may be integrally molded.