A battery pack is made up of a plurality of flat prismatic batteries arranged face to face, each battery having one electrode terminal protruding from one end face in the height direction of the battery case and this end face or a side face of the battery serving as the other electrode terminal. The connector for electrically connecting adjacent prismatic batteries includes a flat part that is welded to one electrode terminal of one prismatic battery of the adjacent prismatic batteries, and a cylindrical part that is fitted onto and welded to the other electrode terminal of the other prismatic battery. The cylindrical part is formed in an attachment part that extends from the flat part through an upright part in the direction in which the batteries are aligned. The connector enables reliable electrical connection of the prismatic batteries despite possible variation in height of the electrode terminals.