Abstract: The invention relates to a brake control device including, a pump driven by an engine, a brake pedal actuated by a vehicle driver, wheel brake cylinders, manual operating means operatively connected with the brake pedal, pressure control valve means having a hollow seat member provided with a normally open-passage therein and a valve seat thereon and conrolling the hydraulic fluid to the pump according to the actuation of the manual operating means, flow regulating valve means having a variable orifice and a fixed orifice and supplying the hydraulic fluid to the passage of the pressure control valve means through the fixed orifice, power piston means actuated according to the actuation of the pressure control valve means, and master cylinders operatively connected with the power piston means for supplying the fluid pressure to the wheel brake cylinders.