CONSTANT VOLTAGE DC SUPPLY DEVICE

To provide a constant voltage DC supply device capable of supplying a direct current at a predetermined voltage for a long time irrespective of characteristics of a storage battery and the like. The constant voltage DC supply device for supplying a direct current at a predetermined voltage from a specific power generation unit, including: a plurality of power storage units ; a drive units that is connected to the power storage units and rotating/driving by power supplied from any one of the power storage units; a plurality of the power generation units connected to the drive units, respectively, and generating power by driving of the drive units; and a control unit for controlling connection between the plurality of power storage units and the driving unit and between the power generation units other than the specific power generation unit and the power storage units , in which wherein the control unit executes control such that, when a voltage of the power storage unit supplying the power to the drive unit falls to a first voltage or less, the power is supplied from the power storage unit other than power storage part and to charge at least one power storage part other than that power storage unit is charged.