Disclosed is an electronic brake system. The electronic brake system comprises a hydraulic pressure supply apparatus generating a hydraulic pressure by using a piston operated by an electrical signal outputted corresponding to a displacement of a brake pedal and including a first pressure chamber provided at one side of the piston movably accommodated in a cylinder block to be connected to one or more wheel cylinders and a second pressure chamber provided at the other side of the piston to be connected to one or more wheel cylinders; a first hydraulic passage communicating with the first pressure chamber; a second hydraulic passage branched from the first hydraulic passage; a third hydraulic passage branched from the first hydraulic passage; a fourth hydraulic passage communicating with the second pressure chamber; a fifth hydraulic passage branched from the fourth hydraulic passage to join with the second hydraulic passage; a sixth hydraulic passage branched from the fourth hydraulic passage to join with the third hydraulic passage; a first control valve provided on the second hydraulic passage to control the flow of oil; a second control valve provided on the third hydraulic passage to control the flow of oil; a third control valve provided on the fifth hydraulic passage to control the flow of oil; a fourth control valve provided on the sixth hydraulic passage to control the flow of oil; a first hydraulic circuit branched from the second hydraulic passage or the fifth hydraulic passage to be connected to two wheel cylinders; and a second hydraulic circuit branched from the third hydraulic passage or the sixth hydraulic passage to be connected to two wheel cylinders.