At least one embodiment of the present disclosure provides an electric hydraulic brake apparatus including a reservoir, a plurality of wheel brake mechanisms, a main braking system, and an auxiliary braking system, wherein the auxiliary braking system includes a first hydraulic pressure input unit and a second hydraulic pressure input unit, a third hydraulic pressure input unit configured to receive brake fluid from the main braking system without passing through booster valves, a first inlet line and a second inlet line configured to transfer a hydraulic pressure between the main braking system and the plurality of wheel brake mechanisms, and a split line configured to receive and supply the brake fluid delivered from the third hydraulic pressure input unit to the plurality of wheel brake mechanisms.