A traction control system is provided variable wheel slippage sensing level depending upon the vehicle speed. Adjustment of the wheel slippage sensing level by varying wheel slippage detecting threshold to be compared with preselected traction control parameter, such as, wheel speed, wheel acceleration and so forth. In practical control, wheel slippage sensability is lowered when the vehicle speed is lower than a given vehicle high speed criterion so as to provide better vehicle stating-up characteristics, and is rised when the vehicle speed is higher than the vehicle high speed criterion so as to provide higher driving stability.