An ABS control apparatus employs a normally-open linear solenoid valve as a pressure-increasing valve, and repeatedly performs ABS control composed of pressure-reducing control and linear pressure-increasing control. This apparatus determines an initial value Pw0 of an estimated wheel cylinder pressure value Pw in consideration of brake operation time before start of ABS control Tstp and vehicle body deceleration at the start of a first-time ABS control, and then determines the estimated wheel cylinder pressure value Pw during the ABS control on the basis of the value Pw0 and the pressure-reducing characteristic of a pressure-reducing valve. This apparatus determines instruction current supplied to the pressure-increasing valve during the linear pressure-increasing control, while using an estimated differential pressure Pdiff (=(Pw0−Pw)+Pup1+Pup2), wherein Pup1 and Pup2 are set in accordance with the time Tstp and additional brake operation during the ABS control, respectively.