A speed changing control system for a vehicle including a speed changing device for speed changing a rotational power from an engine and outputting the resultant power, a speed changing control unit for setting a speed change ratio of the speed changing device, and an engine control unit for setting an engine rotational speed of the engine. Based on an operational instruction in response to a driver's operation, a rotational speed reducing instruction is given to the engine control unit for reducing an engine rotational speed set by the engine control unit by a predetermined amount. Also, a speed changing ratio changing instruction is given to the engine control unit for requesting, to a speed changing control unit, a change of the speed change ratio for compensating for the reduction in the engine rotational speed by the rotational speed reducing instruction so as to maintain the vehicle speed.