PURPOSE: To control the engine torque and speed change ratio by establishing the system for separately controlling a torque converter in used state and in unused state (lock-up control) and securing pour performance and fuel economic efficiency. CONSTITUTION: In the torque control of an internal combustion engine in which the aimed driving shaft torque is obtained from the car speed and the opening degree of an accelerator, and the driving shaft torque of the vehicle is controlled so as to become equal to the aimed driving shaft torque by controlling the gear ratio of a torque transmission mechanism for connecting the output shaft of an engine and the driving shaft of the vehicle and the opening degree of the throttle, the generation of lock-up state for directly connecting the input and output shafts of the torque transmission mechanism is judged (Step 12). The calculation of the effective speed change position is carried out separately according to the result of the judgement (Step 13, 14), and each value of gear ratio and the opening degree of the throttle is made different according to the result of the judgement. Accordingly, the optimum torque control according to the existence of lock-up is enabled. COPYRIGHT: (C)1993,JPO&Japio