An adaptive correction of an inappropriate shift operation is disclosed. During a power-off upshift, a variation in output torque of the transmission output shaft is detected. A decision is made based on this output torque variation whether or not the power-off 1-2 upshift has been effected in a predetermined appropriate manner, and a timing at which an on-coming friction device to be engaged during the power-off upshift is corrected based on the decision made. Thus, the shift operation during the next occurrence of a power-off upshift of the same type is effected in the appropriate manner.