An electrohydraulic brake apparatus includes: a reservoir; a stroke sensor; a plurality of wheel brake assemblies; a main master cylinder; an electric booster; an electronic stability control system; and an electronic control unit configured to control the ESC system so that a fluid pressure supplied to the ESC system brakes only part of the plurality of wheel brake assemblies when the pedaling amount is less than or equal to a first reference, and to control the ESC system so that the fluid pressure supplied to the ESC system brakes all of the plurality of wheels brake assemblies when the pedaling amount is greater than the first reference.