PURPOSE: To control the reduction gear ratio of an AT and the throttle opening so that the driver's operating requirements are fulfilled and fuel consumption is minimized.

CONSTITUTION: A target acceleration setting means 83 sets a target acceleration GT based on a target speed VTX and an actual speed SPD selected by a target speed selection means 82. A target driving torque setting means 84 sets a target driving torque TDRV in accordance with the actual speed SPD and the target acceleration GT. The target driving torque TDRV thus set is input in a reduction speed ration control means 85 which controls the reduction speed ratio and the lockup condition of an AT3 on the basis of the target driving torque TDRV and the target speed VTX so that the target driving torque TDVR can be reached and also the fuel consumption quantity can be minimized. A target throttle opening setting means 86 calculates and sets a target throttle opening TTA on the basis of the actual speed SPD, the target acceleration GT, the reduction speed ratio and the lockup condition.