Disclosed herein are a power supply apparatus, and an electric apparatus and a vacuum cleaner having the power supply apparatus. According to an aspect of the present disclosure, the power supply apparatus includes: a first power converter configured to convert a first Alternating Current (AC) voltage into a Direct Current (DC) voltage; a second power converter configured to drop the DC voltage output from the first power converter and transfer the dropped DC voltage to a power storage unit, and to boost a DC voltage of the power storage unit and output the boosted DC voltage; and a third power converter configured to convert a DC voltage among the DC voltage output from the first power converter and the boosted DC voltage output from the second power converter, into a second AC voltage, and to transfer the second AC voltage to a load.