The anti-skid control system is constructed with a brake fluid pressure source for generating brake fluid pressure at high and low levers, a switching valve feeding either high pressure or low pressure to the wheel cylinders, a wheel velocity detecting device sensing the driving wheel rotating speed, an acceleration detecting device detecting the vehicle acceleration and a first arithmetic operation device for finding the estimated vehicle speed and the wheel rotating acceleration based on the wheel velocity detected by the wheel velocity detecting device and the vehicle body acceleration detected by the acceleration detecting device. A brake fluid pressure controlling device is provided for increasing, decreasing or maintaining the brake fluid pressure in the wheel cylinders, controlling the switching valve on the basis of wheel velocity, estimated vehicle speed, and wheel rotating acceleration. A second arithmetic operation device marks the minimum and maximum values in the wheel velocity after a brake fluid pressure reduction based on the wheel velocity detected by the wheel velocity detecting device calculates the recovery acceleration in the wheel velocity in the shift from the minimum value to the maximum value and compares the recovery acceleration with the set value. A vehicle acceleration correcting device corrects the vehicle body acceleration detected by the acceleration detecting device so as to set the vehicle body acceleration at a smaller value in case the recovery acceleration is less than the set value.