To provide a brake fluid pressure control device capable of obtaining brake fluid pressure having brake operating force increased according to a boosting ratio, on and after an actual boosting force limit point of a negative pressure type power-assisting device for power-assisting the brake operating force.

A master cylinder generates master cylinder fluid pressure by the brake operating force boosted by the negative pressure type power-assisting device. On and after the actual boosting force limit point in which the negative pressure type power-assisting device does not boost the brake operating force by the boosting ratio, assist fluid pressure in relation to the brake operating force on and after the actual boosting limit point is calculated to obtain the brake fluid pressure having the brake operating force increased according to the boosting ratio. The assist fluid pressure is pressurized to the master cylinder fluid pressure generated by the brake operating force by a fluid pressure generating device.