A parameter having an accelerator pedal position and a drive force as components is set according to information representing driver's operations such as the accelerator pedal position and a stroke amount of a brake pedal. Similarly to the information representing the driver's operation, a parameter having the accelerator pedal position and the drive force as the components is set according to information representing running environment of a vehicle such as a gradient of a road surface, a curvature of the road surface, a friction coefficient μ of the road surface, a type of a road and a length of traffic jam. One parameter α(OUT) is set by mediating a parameter α(1) obtained from the information representing the driver's operation and a parameter α(2) obtained from the information representing the running environment of the vehicle. The gear corresponding to the parameter α(OUT) is set.