PURPOSE: To accelerate the brake pressure buildup in a wheel brake especially during rapid braking and traction control, in a hydraulic brake system provided with skid and traction control devices notably for a motor vehicle.

CONSTITUTION: A second shutoff valve 54 installed in a suction line 44 is made to occupy its open position 54a outside a skid control operation, and a throttling part 30 is disposed in a conveyance line 46, between a first shutoff valve 27 and a connection part of the conveyance line 46 to a brake line 17.