The invention discloses a brake booster for a vehicle. The brake booster for the vehicle comprises a first shell and a second shell, the first shell and the second shell are mutually and detectably connected to form a cavity structure, a boosting pushing rod and a braking pushing rod are arranged along a rotating center of the cavity, and the cavity structure is divided into two cavity bodies through an air chamber diaphragm division plate; the boosting pushing rod is located on one side of the first shell, and the braking pushing rod is located on one side of the second shell; one end of thebraking pushing rod extends out of the second shell, and the other end of the braking pushing rod is sequentially connected with the boosting pushing rod through a pushing rod base, an air valve and avacuum valve; a vacuum tube is connected on the end face, away from the first shell, of the second shell; and an elastic auxiliary mechanism is further arranged in the telescopic direction of the braking pushing rod. Through further improvement on the structure of the booster, the pressure difference between the boosting pushing rod and the braking pushing rod is effectively reduced, the reset efficiency of the booster is improved, and the working efficiency of the vacuum booster for the vehicle is improved; and the brake booster is simple in structure and convenient to manufacture and use, and has good using value.