Provided is an electric storage device that can ensure seal in a peripheral area of a portion in a defining wall of a case through which a rivet passes even when a rivet is inserted through the defining wall of the case and the rivet is caulked. The electric storage device includes: an electrode assembly; a case that houses the electrode assembly, the case including a defining wall; and a rivet, wherein a peripheral area of a portion in the defining wall through which the rivet passes has a higher hardness than the remaining area.