A motor drive device that inputs AC power from a power supply to drive a motor includes: a converter that converts the AC power from the power supply into DC power; a DC/DC converter that generates DC power produced by stepping-up, stepping-down, or stepping-up and stepping-down the DC power from the converter; an inverter that converts the DC power from the DC/DC converter into AC power and supplies to the motor; and an electrical storage capacitor that is provided between the DC/DC converter and the inverter.