The present invention relates to a spinal fixing device in which a head portion of a bone screw to be inserted into a vertebra is bound to a housing, and the housing is fixed to a spine rod. The spinal fixing device includes: the housing having a seat portion inside and having a mounting groove for mounting the spine rod a chuck to be inserted into the seat portion, in which a peripheral portion having an elastically changeable diameter and a curved inner circumferential surface is formed along the circumference of the chuck at one side and the bone screw having a spherical head portion to be inserted into the peripheral portion, wherein a surface having a gradually varying diameter is formed on the inner circumferential surface of the seat portion and the outer circumferential surface of the peripheral portion is convex so as to allow the end of the peripheral portion to elastically shrink through the pressure generated between the peripheral portion and the seat portion by pressurization of the chuck by the spine rod, thereby restricting the rotation of the head portion. According to the present invention including said feature, the chuck is combined so as to restrict the head portion of the bone screw and has the peripheral portion having an elastically shrinkable diameter, and thus the movement between the screw and the housing is allowed according to the intention of an operator before being fixed to the spine rod and the movement between the housing and the bone screw can be more effectively inhibited when fixed to the spine rod.
