A power control apparatus comprising: a switch unit provided on a power supply line connecting a system power to a load, wherein the switch unit is configured to interrupt power supply from the system power to the load when the switch unit detects a drop of voltage from the system power below a threshold, the system power being a commercial power supply; a first power control unit connected to the power supply line, wherein the first power control unit is configured to receive a voltage drop signal supplied from the switch unit; a first power storage unit connected to the first power control unit; a second power control unit (14, 17) connected to the power supply line, wherein the second power control unit (14, 17) is configured to receive a discharge start signal supplied from the first power control unit; and a second power storage unit connected to the second power control unit (14, 17); and a rotary machine generator connected to the power supply line, wherein the rotary machine generator is configured to receive an operation control signal supplied from the second power control unit (14, 17) or the second power storage unit, wherein the switch unit is configured, when the switch unit detects the drop of the voltage from the system power below the threshold, to output the voltage drop signal, wherein the first power control unit is configured, when the first power control unit receives the voltage drop signal, to perform control to supply power from the first power storage unit to the load and to output the discharge start signal, wherein the second power control unit (14, 17) is configured, when the second power control unit (14, 17) receives the discharge start signal, to perform control to supply power from the second power storage unit to the load, wherein the second power control unit (14, 17) or the second power storage unit is configured to output the operation control signal when information corresponding to a remaining capacity of the second power storage unit is smaller than a set value, wherein the rotary machine generator is configured, when the rotary machine generator receives the operation control signal, to start operation to supply power to the load. a switch unit provided on a power supply line connecting a system power to a load, wherein the switch unit is configured to interrupt power supply from the system power to the load when the switch unit detects a drop of voltage from the system power below a threshold, the system power being a commercial power supply; a first power control unit connected to the power supply line, wherein the first power control unit is configured to receive a voltage drop signal supplied from the switch unit; a first power storage unit connected to the first power control unit; a second power control unit (14, 17) connected to the power supply line, wherein the second power control unit (14, 17) is configured to receive a discharge start signal supplied from the first power control unit; and a second power storage unit connected to the second power control unit (14, 17); and a rotary machine generator connected to the power supply line, wherein the rotary machine generator is configured to receive an operation control signal supplied from the second power control unit (14, 17) or the second power storage unit, wherein the switch unit is configured, when the switch unit detects the drop of the voltage from the system power below the threshold, to output the voltage drop signal, wherein the first power control unit is configured, when the first power control unit receives the voltage drop signal, to perform control to supply power from the first power storage unit to the load and to output the discharge start signal, wherein the second power control unit (14, 17) is configured, when the second power control unit (14, 17) receives the discharge start signal, to perform control to supply power from the second power storage unit to the load, wherein the second power control unit (14, 17) or the second power storage unit is configured to output the operation control signal when information corresponding to a remaining capacity of the second power storage unit is smaller than a set value, wherein the rotary machine generator is configured, when the rotary machine generator receives the operation control signal, to start operation to supply power to the load.