To provide a power supply device with improved price/performance ratio by improving the working efficiency of a DC/AC inverter and reducing the price of the device for drastically reducing electricity charges utilizing night time power.

The power supply device is provided with a secondary battery 15 for charging a commercial power 11, a current sensor part 31 with a current sensor 31-n for measuring a consumption current for each of a plurality of loads 23-1-N, a switching part 21 with a switch 21-n for switching the commercial power 11 as a power supply for supplying power for each of the plurality of loads and power being charged to the secondary battery 15, and a control part 19 for controlling the switch 21-n based on a consumption current being measured for each of the plurality of loads.