To always keep the running stability of a vehicle in a good state by providing tack-in prevention/control means for bringing the degree of reduction in the output of an internal combustion engine in a tack-in prevention control closer to that in a usual control while a supercharging device is being worked.

After the degree of reduction in a throttle opening is controlled so as to prevent a tack-in phenomenon, if an acceleration pedal is depressed, a supercharging by turbochargers 56, 58 is prevented and, if a supercharging has been performed, the throttle opening of a throttle valve 44 is more reduced to prevent the output of an internal combustion engine 20 from being excessive. To release the depressing of the accelerator pedal when a vehicle is running on a road with a high friction coefficient and to prevent a tack-in phenomenon, an action of preventing the output of the internal combustion engine 20 from being reduced is taken.