Vehicle motion control apparatus

The present invention is directed to a vehicle motion control apparatus, which includes normally open valves to supply hydraulic pressure discharged from a master cylinder into wheel brake cylinders, normally closed valves to reduce wheel cylinder pressure, and a proportional pressure difference valve which is disposed between the master cylinder and the normally open valves, to regulate a pressure difference between the hydraulic pressure at the side of the master cylinder and the hydraulic pressure at the side of the normally open valves to be of a desired value. A pressure generating device is provided for generating the hydraulic pressure independently of the master cylinder to supply it into a passage between the pressure difference valve and the normally open valves. The hydraulic pressure in one of the wheel brake cylinders in one hydraulic circuit is regulated on the basis of monitored vehicle state variable. And, the normally open valve connected to the other one of the wheel brake cylinders in the one hydraulic circuit is controlled in response to the pressure regulated in the one of the wheel brake cylinders, when the brake pedal is operated while the pressure generating device is being controlled on the basis of the vehicle state variable.