Method of controlling hydraulic brake system for vehicle

A method of controlling a hydraulic pressure source-drive type vehicle hydraulic brake system which would not make the driver feel a delay in the effect of braking, and in which the braking force acts quickly and reliably even during urgent braking. A stroke sensor for detecting the pedal depressed amount in the initial play area is provided. By activating a motor for a pump for supplying brake fluid to a wheel cylinder beforehand when the stroke sensor detects that the pedal depressed amount has reached a predetermined threshold, the time needed to depress the brake pedal to the terminal position of the initial play area and the delay time in response of the actuation of the motor are overlapped to shorten the time from the start of depressing of the brake pedal to the actuation of the brake.