A method of limiting a load applied on a seat belt in an emergency, includes obtaining information, judging if the emergency situation is in a first situation wherein a predetermined condition for controlling one seat belt load limiting mechanism is not satisfied based on the information, or in a second situation wherein the predetermined condition is satisfied; and in the first situation, the method further performs actuating a driving member not to operate the one seat belt load limiting mechanism, winding the seat belt to remove a slack of the seat belt with actuating the driving member, and operating another seat belt load limiting mechanism to prevent withdrawing the seat belt; and in the second situation, the method further performs winding the seat belt without actuating the driving member, and operating the one and another seat belt load limiting mechanisms to prevent withdrawing the seat belt.