There is provided an electric storage device in which an electrode assembly enclosed in an insulating cover can be smoothly inserted in a case and the electrode assembly is positioned in place inside the case when housed in the case. The electric storage device according to the present invention includes an electrode assembly, an insulating cover covering the electrode assembly, and a case including a case body having a rectangular box shape and having an opening, the case body being configured to house the electrode assembly and the insulating cover, wherein the insulating cover is formed into a rectangular box shape conforming to the case body, and a portion of each of edges at which adjacent side surfaces of the insulating cover meet each other is beveled into a beveled part, the portion being close to the bottom of the insulating cover.