To provide a battery or capacitor capable of reducing insulating parts interposed between an external terminal and a case still having an insulation property between the external terminal and the case.

This battery or capacitor has a case 30 of an aluminum or aluminum alloy, an electrode body 40 composed of a positive electrode 24 and a negative electrode 26 housed in the case 30 and an external terminal 12 connected to the positive electrode 24 and the negative electrode 26 and penetrated through the case 30 as being electrically insulated. The case 30 is formed with an alumite film 18 at least on the position through which the external terminal 12 pierces and is electrically insulated by the alumite film 18. The case 30 coated with the alumite film 18 has an electric insulation property so that no insulating part needs to reside between the external terminal 12 and the case 30. Thus, this has effects to reduce the number of part items.