A spine fixation device is provided. The spine fixation device includes a bone screw, a fixation carrier, and a first locking member. The fixation carrier is rotatably coupled to a fixation unit of the bone screw. The first locking member conjugates the fixation carrier and the bone screw together. A screw unit of the bone screw is implanted into a vertebra. As the fixation carrier is rotatably coupled to the bone screw, the bone screw remains fastened to the vertebra while the fixation carrier is rotated. Through rotational adjustment of the fixation carrier, U-shaped openings of the fixation carrier are adjustable in direction. Thus, the disposition angle of a rod disposed in the U-shaped openings is easily adjustable by rotating the fixation carrier. As a result, the rod can fit an angle of the spine while surgical complexity is reduced.