PURPOSE: To make a continuous travelling possible even when such a trouble as cutting off the supply of injection fuel and stopping an engine is generated by sucking fuel staying in a regular fuel chamber from a fuel port positioned on the throttle valve side by means of a negative suction pressure, and supplying it to the engine.

CONSTITUTION: When a fuel injection device 7 is controlled by an electronic control system, and a fuel injection valve 8 supplies fuel in accordance with the operation state of an engine 6, an open/close valve 38 is closed and does not feed fuel to a regular fuel chamber 29. A trouble, then, is generated and a fail-safe proceeding that cuts off fuel and stops the engine is to be actuated, a valve opening signal is sent from a control device 14 to the open/close valve 38, and a fuel pump 37 that has been already operating or started to operate simultaneously with the valve opening feeds fuel to the regular fuel chamber 29. And, when the engine 6 is continuously rotating or restarted after once stopped, a throttle valve 1 is opened and a fuel port 24, which the negative suction pressure of the engine 6 is acting on, sucks the fuel in the regular fuel chamber 29. Thus, the self travelling to the destination or servicing factory is possible.