To make a capacitor for a power compact by reducing a space in a container in which a capacitor element body having a dummy insulating board with a discharge resistance is housed.

A plurality of capacitor elements 1 are piled up on a set insulating board 3, and a dummy insulating board 2 is placed on the capacitor element 1 positioned at the top, and the set insulating board 3 is overlapped on that, and the whole body is tightly tied with a band 8 so that a capacitor can be configured. A clearance 7 is formed with the dummy insulating board 2, and discharge resistors connected to the capacitor elements 1 are inserted into the clearance 7. Thus, it is possible to reduce a space in the capacitor container.