Apparatus for generating braking force in a vehicle brake system has at least two pressure supply devices and first and second hydraulic brake circuits, each having at least one or two hydraulic wheel brakes. Pressure in at least one brake circuit can be both built up and released by the pressure supply devices, which include a piston pump or gear pump driven by an electric motor drive and deliver continuous volume. At least one valve arrangement may adjust wheel brake pressures individually and/or disconnect/connect the wheel brakes from/to a brake circuit and/or a pressure supply device. At least one electronic control unit enables open-loop and closed-loop control. Pressure increase is enabled in one or both brake circuits, independently or in combination, using first and/or second pressure supply devices that produce changes in pressure simultaneously or temporally offset or overlapping.