An electric brake system includes a hydraulic pressure supply device configured to generate hydraulic pressure using a piston which is operated by an electrical signal that is output corresponding to a displacement of a brake pedal, and including a first pressure chamber and a second pressure chamber, a first hydraulic flow path configured to communicate with the first pressure chamber, a second hydraulic flow path configured to communicate with the first pressure chamber, a third hydraulic flow path configured to communicate with the second pressure chamber, a fourth hydraulic flow path branching from the third hydraulic flow path and connected to the first hydraulic flow path, a fifth hydraulic flow path branching from the third hydraulic flow path and connected to the second hydraulic flow path.