With the present invention, it is possible for a vehicle to run on an uphill road at substantially the same throttle opening as on a horizontal road. When the road is uphill (hill-climbing resistance R.theta.>0), a maximum acceleration Amax for a full throttle opening is obtained according to a vehicle speed, and a maximum driving force Fmax=m.multidot.Amax+RL is calculated based on the mass of the vehicle m and the rolling and air resistance RL of the vehicle. Then, a correction coefficient HOS is obtained according to a throttle opening to calculale a required driving force Ftgt=Fmax.multidot.HOS. According to the required driving force Ftgt, hill-climbing resistance R.theta., and vehicle speed VSP, a target horsepower Ptgt=(Ftgt+R.theta.).multidot.VSP is calculated. To attain the target horsepower Ptgt, a target speed change ratio "itgt" for a continuously variable transmission is calculated to control the transmission.