ELECTRICITY STORAGE DEVICE

Provided is a technique for suppressing a surface pressure of an electrode assembly from becoming non-uniform. A herein disclosed electricity storage device includes an electrode assembly, a case, and a spacer. An outer surface of the electrode assembly includes a first surface on one of end parts in a laminate direction, a second surface on the other end part in the direction, and a third surface between the first surface and the second surface. The first surface, the second surface, and the third surface are configured by the separator. A first end part in a longitudinal direction of the separator is arranged on the third surface. The separator includes a first area containing the first end part and arranged on the third surface. The first area is configured to cover a part of the spacer, and a joint part where the first area is joined to the spacer.