An electric storage cell has an electric storage element and a covering film package. The covering film package houses the electric storage element and includes: a metal layer having a first principle face on the electric storage element side and a second principle face on the opposite side of the first principle face, an internal resin layer laminated to the first principle face, and an external resin layer laminated to the second principle face, with a slit formed in the external resin layer; wherein the contact area further includes a non-seal area between the seal area and the electric storage element as viewed from above, wherein the seal area has a projecting area that penetrates into the non-seal area, and the slit is provided between the projecting area and the electric storage element as viewed from above.