ELECTRONIC BRAKE SYSTEM

Disclosed herein an electronic brake system includes a reservoir provided with spaces for storing oil, the spaces configured to be partitioned; a master cylinder connected to the reservoir, the master cylinder including first and second master chambers and first and second pistons provided in each master chamber, to discharge oil according to a pedal effort of a brake pedal; a hydraulic pressure supply device operated by an electrical signal to generate hydraulic pressure and including first and second pressure chambers and a hydraulic piston; a first hydraulic circuit configured to transmit hydraulic pressure discharged from the hydraulic pressure supply device to wheel cylinders of left front and right front wheels; and a second hydraulic circuit configured to transmit hydraulic pressure discharged from the hydraulic pressure supply device to wheel cylinders of left rear and right rear wheels; wherein hydraulic pressure returned from the wheel cylinders and hydraulic pressure returned from the second pressure chamber flow into the same reservoir chamber.