Provided is an energy storage device which includes: an electrode assembly where electrodes are layered to each other; and current collector joined to the layered electrodes in a state where the current collector overlaps with the electrodes. The electrode and the current collector are welded to each other or are joined to each other by ultrasonic bonding at a first joint portion. At least one of the electrode and the current collector includes a wall surface which projects from a periphery of the first joint portion or a region adjacent to the periphery along a stacking direction of the electrode and the current collector, and surrounds the first joint portion. The wall surface is disposed on both sides of the first joint portion in the stacking direction.