A direct-current bus power supply as a power supply device supplies power to a load capable of switching a state between a driving state in which driving is performed by receiving power supply and a standby state in which driving is stopped while receiving power supply. The power supply device includes: a diode bridge circuit and capacitors as a rectifier circuit that enables an alternating-current voltage to be rectified by respective rectification systems of full-wave rectification and voltage doubler rectification; and a switching unit that perform switching between the full-wave rectification and the voltage doubler rectification on the basis of a voltage value of the alternating-current voltage and the state of the load.