An engine control device capable of decreasing engine output while giving less uncomfortable feeling to the rider in the event of a failure, with a simple configuration. Engine output is decreased when a failure has been detected in a throttle valve. When engine speed after the occurrence of the failure is larger than preset target rotational speed at the time of the occurrence of the failure, an ignition of the engine is cut off. The engine speed thereby can be decreased according to the preset target rotational speed. Thus, engine output can be decreased uniquely.