A control device includes a control circuit configured to control an inverter circuit that drives a motor by a plurality of switching elements coupled between DC buses, a first power supply system using a voltage source different from the DC buses as a power supply, a second power supply system using the DC buses as a power supply, and a switching circuit configured to switch a power supply system that supplies power to the control circuit from the first power supply system to the second power supply system when an abnormality in the first power supply system is detected. The control circuit continues control of the inverter circuit with a power consumption lower than that before the abnormality is detected in the first power supply system, when the abnormality is detected.