An electric storage device, comprising: an electrode assembly including a positive electrode foil and a negative electrode foil, which are wound with an insulator interposed therebetween and laminated into a multilayer in a mutually insulated state, the electrode assembly having at least one protrusion portion (8A), the protrusion portion being formed of one end portion of a pair of end portions in the direction of an axis of one of the positive electrode foil and the negative electrode foil and protruding in a laminated state from the end portion in the direction of the axis of the other one of the electrode foils (7,8); a current collector having a contact portion in contact with the protrusion portion (8A); a metal material to be laid on the protrusion portion (8A), the protrusion portion (8A) being interposed between the contact portion of the current collector and the metal material, the protrusion portion (8A) including a pair of straight portions (8a) located on opposite sides with the axis of the electrode assembly therebetween; the contact portion of the current collector being disposed between the pair of straight portions (8a); and the metal material having an opposing face opposed to one of the pair of straight portions (8a); wherein the central region of the opposing face of the metal material and the contact portion of the current collector are joined to the one of the pair of straight portions (8a), characterized in that among end regions (26A∼29A) of the opposing face of the metal material, at least one end region (28A) in one direction along the opposing face is displaced in a direction away from the contact portion of the current collector compared to a central region of the opposing face, wherein the end region (28A) of the opposing face of the metal material is formed into a tapered surface which is inclined such that a displacement amount in a direction away from the contact portion of the current collector gradually increases towards an outer edge of the metal material. an electrode assembly including a positive electrode foil and a negative electrode foil, which are wound with an insulator interposed therebetween and laminated into a multilayer in a mutually insulated state, the electrode assembly having at least one protrusion portion (8A), the protrusion portion being formed of one end portion of a pair of end portions in the direction of an axis of one of the positive electrode foil and the negative electrode foil and protruding in a laminated state from the end portion in the direction of the axis of the other one of the electrode foils (7,8); a current collector having a contact portion in contact with the protrusion portion (8A); a metal material to be laid on the protrusion portion (8A), the protrusion portion (8A) being interposed between the contact portion of the current collector and the metal material, the protrusion portion (8A) including a pair of straight portions (8a) located on opposite sides with the axis of the electrode assembly therebetween; the contact portion of the current collector being disposed between the pair of straight portions (8a); and the metal material having an opposing face opposed to one of the pair of straight portions (8a); wherein the central region of the opposing face of the metal material and the contact portion of the current collector are joined to the one of the pair of straight portions (8a), characterized in that among end regions (26A∼29A) of the opposing face of the metal material, at least one end region (28A) in one direction along the opposing face is displaced in a direction away from the contact portion of the current collector compared to a central region of the opposing face, wherein the end region (28A) of the opposing face of the metal material is formed into a tapered surface which is inclined such that a displacement amount in a direction away from the contact portion of the current collector gradually increases towards an outer edge of the metal material.