An energy storage apparatus includes: an outer case having a box-shaped outer case and a lid covering one side of the outer case body in a predetermined direction; and an inner lid disposed on one side of one end portion of the energy storage device on the one side in the predetermined direction. The outer case body includes a pair of first side walls facing each other, and a pair of first fixing portions that are respectively provided on the pair of first side walls and attach the inner lid. The inner lid includes a pair of second fixing portions that are respectively connected with the pair of first fixing portions and are arranged at a predetermined distance from each other. The outer case body and the inner lid are fixed by connecting the pair of first fixing portions and the pair of second fixing portions with each other.