A brake hydraulic pressure control device for a vehicle, the control device comprising: a hydraulic pressure adjustment unit that is configured to carry out adjustment involving individually increasing/decreasing brake hydraulic pressures applied to wheel brakes (BA, BB) for coaxial front wheels (WA, WB) and wheel brakes (BC, BD) for coaxial rear wheels (WC, WD) in order to prevent the front wheels (WA, WB) and the rear wheels (WC, WD) from attaining a locked state when braking; allowable differential pressure setting means that is configured to set an allowable differential pressure between the brake hydraulic pressures of the wheel brakes (BA, BB) for the coaxial left and right front wheels (WA, WB) and an allowable differential pressure between the brake hydraulic pressures of the wheel brakes (BC, BD) for the coaxial left and right rear wheels (WC, WD), operation of the hydraulic pressure adjustment unit being controlled so that the differential pressure between brake hydraulic pressures of the left and right wheel brakes (BA, BB; BC, BD) is no greater than the allowable differential pressure that is set by the allowable differential pressure setting means; and hydraulic pressure acquisition means that is configured to acquire a lock hydraulic pressure, which is a hydraulic pressure when starting anti-lock brake control for the respective wheel brake (BA to BD), wherein the allowable differential pressure setting means is configured to set the allowable differential pressure so as to correspond to a coefficient of friction of a road surface on which the vehicle is traveling, characterized in that at the time of anti-lock brake control the hydraulic pressure acquisition means is configured to acquire the hydraulic pressure of the wheel brake for the other wheel that is coaxial with the control target wheel, and the allowable differential pressure setting means is configured to set the allowable differential pressure corresponding to the coefficient of friction of the road surface based on the larger hydraulic pressure between the lock hydraulic pressure acquired by the hydraulic pressure acquisition means and the hydraulic pressure of the wheel brake for the other wheel that is coaxial with the control target wheel, and when the lock hydraulic pressure of the wheel brake (BA, BB) for either one of the coaxial left and right front wheels (WA, WB) acquired by the hydraulic pressure acquisition means is no greater than a predetermined value which can be determined as to be a low coefficient of friction, application of the allowable differential pressure corresponding to the coefficient of friction of the road surface is prohibited. a hydraulic pressure adjustment unit that is configured to carry out adjustment involving individually increasing/decreasing brake hydraulic pressures applied to wheel brakes (BA, BB) for coaxial front wheels (WA, WB) and wheel brakes (BC, BD) for coaxial rear wheels (WC, WD) in order to prevent the front wheels (WA, WB) and the rear wheels (WC, WD) from attaining a locked state when braking; allowable differential pressure setting means that is configured to set an allowable differential pressure between the brake hydraulic pressures of the wheel brakes (BA, BB) for the coaxial left and right front wheels (WA, WB) and an allowable differential pressure between the brake hydraulic pressures of the wheel brakes (BC, BD) for the coaxial left and right rear wheels (WC, WD), operation of the hydraulic pressure adjustment unit being controlled so that the differential pressure between brake hydraulic pressures of the left and right wheel brakes (BA, BB; BC, BD) is no greater than the allowable differential pressure that is set by the allowable differential pressure setting means; and hydraulic pressure acquisition means that is configured to acquire a lock hydraulic pressure, which is a hydraulic pressure when starting anti-lock brake control for the respective wheel brake (BA to BD), wherein the allowable differential pressure setting means is configured to set the allowable differential pressure so as to correspond to a coefficient of friction of a road surface on which the vehicle is traveling, characterized in that at the time of anti-lock brake control the hydraulic pressure acquisition means is configured to acquire the hydraulic pressure of the wheel brake for the other wheel that is coaxial with the control target wheel, and the allowable differential pressure setting means is configured to set the allowable differential pressure corresponding to the coefficient of friction of the road surface based on the larger hydraulic pressure between the lock hydraulic pressure acquired by the hydraulic pressure acquisition means and the hydraulic pressure of the wheel brake for the other wheel that is coaxial with the control target wheel, and when the lock hydraulic pressure of the wheel brake (BA, BB) for either one of the coaxial left and right front wheels (WA, WB) acquired by the hydraulic pressure acquisition means is no greater than a predetermined value which can be determined as to be a low coefficient of friction, application of the allowable differential pressure corresponding to the coefficient of friction of the road surface is prohibited.