In the present invention, an electricity storage device has at least one electrode comprising one metal tab lead and a plurality of electrode plates. Each of the plurality of electrode plates has metal foil, an undercoating layer formed on one or both surfaces of the metal foil, and an active substance layer formed on the surface of the undercoating layer. The undercoating layer contains a carbon material and has a basis weight per one surface of 0.01 to 3 g/m2. The total thickness of metal foil in the plurality of electrode plates is 0.2 to 2 mm, and the plurality of electrode plates are welded to each other and to the metal tab lead at the portion where the undercoating layer is formed.