Abstract: An anti-skid control system includes a hydraulic pressure generator for generating hydraulic brake pressure, hydraulic pressure control valves which control the brake hydraulic pressure of the wheel cylinders, wheel speed sensors for detecting the rotational speed of the wheels, and a controller for controlling the hydraulic pressure control valves to decompress or pulse-boost the brake hydraulic pressure in the wheel cylinders based on the output signal of the wheel speed sensors. A brake pedal depression amount detecting device detects the amount of depression of the brake pedal. The controller includes a road surface change judging device for judging that the road surface has shifted from a surface having a low coefficient of friction to a surface having a high coefficient of friction when a continuous run pulse number or a continuous run time of the pulse boost control exceeds a preset value.