A power control device includes an electric power storage device connected across a power supply line for a load and including at least one electric double layer capacitor (EDLC) bank and a secondary battery combined with the EDLC bank, the EDLC bank including a plurality of parallel-connected rows of EDLC unit cells, each of the rows including a plurality of series-connected EDLC unit cells, and a control device controlling the electric power storage device so that when an input power to the electric power storage device is interrupted, the EDLC bank supplies electric power to the load for an initial period of the power interrupt and subsequently, the secondary battery supplies electric power to the load.