Abstract: A case (2) houses positive electrodes and negative electrodes of an electrical double layer capacitor. An insulator (10) is so arranged as to cross four surfaces around the case (2). Positive electrode side terminals (21) are welded on respective positive electrodes (20) of a capacitor main body (11). The positive side terminals (21) are bundled together, and are electrically connected to a connection portion (22) which is formed on an inner wall surface of a divided surface (3A) of a first side surface (3) constituting the case (2). Negative electrode side terminals (31) are welded on respective negative electrodes (30) of the capacitor main body (11). The negative electrode side terminals (31) are bundled together, and are electrically connected to a connection portion (32) which is formed on an inner wall surface of a divided surface (3B) of the first side surface (3) constituting the case (2).