A brake boost control apparatus has a brake operation member, a master cylinder, a wheel cylinder, a hydraulic pump, a master cylinder pressure detection section detecting a pressure of the brake fluid, a brake stroke amount detection section detecting a stroke amount of the brake operation member, a hydraulic pressure control section that controls a pressure of the wheel cylinder, a boost section which boosts the pressure of the brake fluid and increases the wheel cylinder pressure, and a control unit. The control unit controls at least one of the hydraulic pump and the hydraulic pressure control section so that the stroke amount detected by the brake stroke amount detection section under a boost operation by the boost section and the pressure detected by the master cylinder pressure detection section are maintained at a predetermined relationship.