The present invention provides a gas adsorbent that can remove aldehydes with high efficiently while depressing aged degradation in aldehyde removal performance during storage. The gas adsorbent according to the present invention is a gas adsorbent including inorganic porous bodies in combination with a water-soluble acid hydrazide compound and a compound having a thiol-based functional group, with the latter compounds being supported on the former bodies. Cysteine is used as the compound having a thiol-based functional group.
