A power control apparatus has a switch configured to interrupt power supply from a system power when the switch has detected a drop of voltage from the system power below a threshold, a first power controller configured to receive a voltage drop signal supplied from the switch unit, a first power storage unit connected to the first power controller, a second power controller configured to receive a discharge start signal supplied from the first power controller, a second power storage unit connected to the second power controller, and a rotary machine generator that receives an operation control signal supplied from the second power controller or the second power storage unit.