A brake device for a vehicle is provided in which when there is an abnormality in which a slave cylinder becomes incapable of being actuated, a wheel cylinder is actuated using a brake fluid pressure generated by a master cylinder, which is actuated by a brake pedal. Since an idling detector detects idling of a motor when the rotational speed of the motor is greater than a reference value that is set according to the stroke of the slave cylinder, it is possible to reliably and rapidly detect idling of the motor. When the idling of the motor is detected, since a control device opens a master cut valve and the wheel cylinder is actuated by the brake fluid pressure generated by the master cylinder, the slave cylinder, which has become incapable of being actuated, can be backed up rapidly by the master cylinder.