Bone fixation apparatus

The invention claims a bone fixing device. The device comprises: Head bone screw; Arranged on the bone bolt upper cover cap; With a hole and a u-shaped groove containing unit; the hat and bone head bolt is respectively and keeping, wherein the hole, a support rod connected through the u-shaped slot is extended; With a thread on the element is downward bias supporting rod and element. A step shape of form, wherein a support elements wherein a lower end and inner surface to with the lower outer surface of the head, adding to murex pin head of the pressure.