PURPOSE: To make it possible to precisely control a power train, by totally controlling both engine and transmission unit in accordance with a control theory based on a preferential order upon transient operation.

CONSTITUTION: Transient operation in the operating condition of an engine 3 is discriminated in accordance with the operated amounts of an accelerator pedal, a brake pedal, a parking brake lever, a select lever, a crank angle, a crank shaft torque, an intake-air flow rate, a temperature, etc. With the result of this discrimination, the preferential order of control steps is determined, corresponding to the transient operation, and therefore, a control unit 1000 controls both engine 1 and transmission unit 4 in accordance with a total control theory based upon the above-mentioned preferential order. With this arrangement, the engine and transmission unit may be totally controlled, taking suitable timing with respect to the order of preference. Thus, other operating instructions having high preferential orders, if any in a certain program, can be at once processed, thereby highly responsive control with a high degree of accuracy may be expected.