This paper presents a study on the application of the sliding mode control to the development of the servo control system of brakes in a vehicle. At first, a preliminary method was developed and evaluated by actual vehicle experiments. From those results, it was found that the robustness could not be assured in some cases, because the output response was delayed by the saturation of the control input and by the existence of the lags of sensors and actuators ignored in the controller design. To avoid these problems, the adaptive sliding mode control was then newly developed by the method that the magnitude of the nonlinear part of the input was changed adaptively by introducing the tire model into the control algorithm and by estimating the parameter changes.