PURPOSE: To prevent the deterioration of the drive feeling due to the shift-down caused by the change from the normal mode to the speed change pattern in power mode when the duration period exceeds a standard period set on the basis of a prescribed parameter value representing the traveling state.

CONSTITUTION: A throttle opening degree signal TVO and a car speed signal VS are read into a CPU 6, and the throttle opening degree signal TVO is read at the starting point and the end point after the lapse of a prescribed time which are set by a timer 9. Then, the variation speed of the throttle opening degree, i.e., the variation speed of the engine load is obtained by dividing the increase of the throttle opening degree within the lapse of a prescribed time by the lapse of a prescribed time. When the duration period where the state where the variation speed of the throttle opening degree is larger than a prescribed value exceeds a standard period determined from a prescribed map, the speed change map in power mode is selected. Accordingly, during the traveling in the normal mode, the speed change map is changed to power mode, while in the traveling in power mode, the mode is maintained.