PURPOSE: To improve operation comfortability by means of a simple fluid circuit constitution and to provide an easily manufacturable anti-lock control type hydraulic brake system for an automobile.

CONSTITUTION: In the middle of a pipeline of a main pressure conduit 7 communicated with a master cylinder 4, a hydraulic diaphragm valve 3 provided with a first control conduit 1 connected to the main pressure conduit 7 and a second control conduit 2 is arranged. The hydraulic diaphragm valve 3 controls supply and shutoff of pressure fluid from the master cylinder 4 to the wheel brake 3. In an anti-lock control time, the diaphragm valve 3 is throttled so as to prevent a drop of a brake pedal.