ENERGY STORAGE DEVICE

An energy storage device includes an outer case including a lid plate on which an external terminal is mounted, a plate including a tab and housed in the outer case, a conductive shaft portion penetrating the lid plate and including one end thereof connected to the external terminal, and a conductive plate portion housed in the outer case, and including a first surface to which an other end of the conductive shaft portion is connected and a second surface to which the tab is connected. A size of the conductive plate portion is set larger than a size of the external terminal in a planar direction of the lid plate.