An automatic shifting-operation control system having an engine control unit that controls the operation of an engine by a signal of an intake air amount detected by intake air amount detecting unit which detects an intake air amount of an engine, and which includes one or both of a vehicle speed limiting function for reducing a fuel injection amount to suppress a driving speed of a vehicle to a speed equal to or less than a predetermined limited value, and a cruise control function for setting the driving speed of the vehicle to an optional constant speed capable of allowing an automatic cruise of the vehicle, and a transmission control unit configured to control a transmission in accordance with a driving state of the vehicle. The transmission can be automatically controlled in the like manner as that of the normal driving state even when the vehicle is driving with a reduced fuel injection amount by the vehicle speed limiting function or even during the automatic cruise due to the cruise control function of the engine control unit.