a reservoir in which a pressurized medium is stored;

an integrated master cylinder comprising a first simulation chamber, a second simulation chamber, a first master chamber and a second master chamber having a smaller diameter than the second simulation chamber, a first simulation piston provided to pressurize the first simulation chamber and be displaceable by a brake pedal, a second simulation piston provided to pressurize the second simulation chamber and the first master chamber and be displaceable by a displacement of the first simulation piston or a hydraulic pressure of the first simulation chamber, a master piston provided to pressurize the second master chamber and be displaceable by a displacement of the second simulation piston or a hydraulic pressure of the first master chamber, an elastic member provided between the first simulation piston and the second simulation piston, a first simulation flow path to connect the first simulation chamber and the reservoir, and a first simulator valve provided in the first simulation flow path to control a flow of the pressurized medium;

a reservoir flow path to connect the integrated master cylinder and the reservoir;

a hydraulic pressure supply device configured to generate a hydraulic pressure by operating a hydraulic piston according to an electrical signal output in response to a displacement of the brake pedal, and comprising a first pressure chamber provided on one side of the hydraulic piston accommodated to be movable in a cylinder block and connected to one or more wheel cylinders, and a second pressure chamber provided on another side of the hydraulic piston and connected to the one or more wheel cylinders;

a hydraulic control unit having a first hydraulic circuit configured to control a hydraulic pressure transferred to two wheel cylinders and a second hydraulic circuit configured to control a hydraulic pressure transferred to other two wheel cylinders; and

an electronic control unit configured to control valves based on hydraulic pressure information and displacement information of the brake pedal,

wherein the hydraulic control unit comprises a first hydraulic flow path in communication with the first pressure chamber, a second hydraulic flow path in communication with the second pressure chamber, a third hydraulic flow path in which the first hydraulic flow path and the second hydraulic flow path join, a fourth hydraulic flow path branched from the third hydraulic flow path and connected to the first hydraulic circuit, a fifth hydraulic flow path branched from the third hydraulic flow path and connected to the second hydraulic circuit, a sixth hydraulic flow path in communication with the first hydraulic circuit, a seventh hydraulic flow path in communication with the second hydraulic circuit, an eighth hydraulic flow path in which the sixth hydraulic flow path and the seventh hydraulic flow path join, a ninth hydraulic flow path branched from the eight hydraulic flow path and connected to the first pressure chamber, and a tenth hydraulic flow path branched from the eight hydraulic flow path and connected to the second pressure chamber.