An anchor pretensioner structure for cars, may include an inflator mounted on a car-body plate to pull a seat belt upon a collision, a pretensioner wire made of a flexible material and connected to the inflator, a protector mounted to the pretensioner wire coupled to the seat belt, and an angle-adjuster to selectively rotate the pretensioner wire, depending upon whether or not a passenger may be sitting on a seat, so that the pretensioner wire may be allowed to rotate by a predetermined angle.