After a remote control valve has been brought into a non-working state, a stop signal is to be sent from an engine controller in a controller to a governor controller in an engine to stop the engine automatically, under the condition that an illuminating lamp is turned off, after a preset allowance time has passed and when a gate lever provided at a gateway for an operator is opened (the operator gets off the machine). Further, before the engine is stopped, the operator is to be notified of the coming engine stop, and when the engine is stopped, a power supply is to be cut off automatically.