During power running operation of a load, a control unit turns off a switch unit to supply AC power from an uninterruptible power supply unit to the load. During regenerative operation of the load, in a case where an AC power supply can recover regenerative power, the control unit turns off the switch unit to supply the regenerative power to the AC power supply via the uninterruptible power supply unit. In contrast, in a case where the AC power supply cannot recover the regenerative power, the control unit turns on the switch unit to cause an auxiliary load unit to consume the regenerative power.