To provide an inexpensive voltage-drop countermeasure device that can operate all load devices as much as possible by effectively utilizing accumulated electric energy, while optimizing the timing of limiting the load devices to be operated to some devices at an instantaneous power drop or power failure.

In a memory of a control unit of the voltage-drop countermeasure device that feeds the accumulated power to the load devices from the electric storage device when an instantaneous power drop or a power failure with a commercial power supply occurs, a timing TC in which a first attenuation curve CL1 of an output voltage of the electric storage device at electric power supply to all the load devices and a second attenuation curved line CL2 of the output voltage of the electric storage device at electric power supply to a part of the load devices intersect with each other, is set in advance. When an elapsed time from the instantaneous power drop or the power failure reaches the timing TC, objects to be supplied with power from the electric storage device are limited to some of the load devices from all the load devices.

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