In a traction control system, an initial engine torque for a traction control is selected from the following engine torques: an engine torque calculated from a throttle opening degree and an engine revolution-number; a required engine torque calculated from a total acceleration and a vehicle speed; and an engine torque corresponding to a road surface of an extremely low friction coefficient, depending upon a slipping state determined by comparing a driven wheel speed with slip reference values. When the driven wheel speed repeatedly exceeds the slip reference value, it is determined that a hunting has been generated, and the engine torque corresponding to the road surface of the extremely low friction coefficient is selected, and the engine torque is largely reduced. Thus, when the friction coefficient of the road surface is low, the driven wheel speed is prevented from hunting.