To provide a DC power supply which utilizes a capacitor for supplying a DC power source of a heavier current, in a voltage higher than the DC voltage supplied from a battery by utilizing a large capacitance capacitor and a battery.

The DC power supply which utilizes the capacitor comprises the battery B with one end grounded to output a first DC voltage, a first capacitor C21 with one end coupled with the other end of the battery and with the end of a node to output a second DC voltage boosted with the first DC voltage and a charging controller 100 for detecting the voltage of the other end of the first capacitor and transfers, when the detected voltage is the prescribed level or lower, the energy charged in the second capacitor to the first capacitor with the prescribed switching operation, by controlling the charging of a built-in second capacitor C22 having first DC voltage and stops magnetic oscillation, when the detected voltage is the prescribed level or higher.