A package construction has electrodes of a double layer capacitor element located on the opposite sides of the element. All of the electrodes are led out in the same direction. A pair of electrode plates are disposed on the element with an insulator plate having a through-hole interposed between the two plates. A terminal of an inner electrode plate penetrates through the through-hole in the insulator plate and through an aperture formed in the outer electrode plate. The capacitor is assembled in such manner that the inner electrode plate is electrically connected to one electrode of the element, while the outer electrode plate is electrically connected to the other electrode of the element via a conductive casing.