To allow respective systems to control power supply to their own systems independently, thus reducing power consumption.

A controller device 21, an engine device 22, and a peripheral device 23 decentrally perform system end processing in a parallel manner and each stops power supply thereto by itself at timing when the own system end processing is completed. Thereby, during completion of operations performed when a power switch 13 is turned off, continuation of power supply to the device irrelevant to the operations is prevented, so that useless power consumption can be prevented.