To improve precision in discriminating a defect in a front-wheel brake system during implementation of rollover suppression control.

Included are: a braking system 30 including a brake system for front wheels and a brake system for rear wheels; and a defect determination block 1e that determines the possibility of a defect in the brake system for front wheels in the case behavior stabilization control is implemented during turning of a vehicle, a master cylinder pressure exceeds a predetermined value, a deceleration of the vehicle 10 is smaller than a reference determination threshold, and ABS (Anti-lock Brake System) control is not implemented in the front wheels Wfl and Wfr. If rollover suppression control is implemented during turning of the vehicle, the defect determination block 1e sets a determination threshold which is compared with the deceleration of the vehicle 10, to a value smaller than the reference determination threshold.