To provide a hydraulic brake system that is low in manufacturing cost.

A first pressure intensifying valve 5 and a pressure fluctuating valve 6 are interposed in series in a first supply passage 3 interconnecting a master cylinder 2 and a wheel cylinder 4. A second pressure intensifying valve 16 is interposed in a second supply passage 14 interconnecting a hydraulic pressure source 8 and the wheel cylinder 4. The first supply passage 3 branches, between the first pressure intensifying valve 5 and the pressure fluctuating valve 6, into a return passage 17, which interconnects the wheel cylinder 4 and a reservoir 12 and in which a pressure reducing valve 18 is disposed. The second pressure intensifying valve 16 is a normally closed type that keeps it closed in normal conditions.