The present invention relates to a ball cage that can be applied to a structure such as inteom shaft is used for the steering wheels of the vehicle. The ball cage has a plurality of round as a ball cage disposed between the solid shaft to be inserted into the hollow shaft and the hollow shaft is mounted so that the plurality of ball bearings can be a rolling movement relative to the hollow shaft and the solid shaft, outer holes are spaced apart in the outer cage, and the inner side from the outer cage to be formed, and a plurality of inner hole inner cage which is formed corresponding to the plurality of the outer holes in the circumference, the ball bearing is the and the outer holes It is arranged to prevent the escape between the inner hall. According to the present invention, there can be eliminated the need to have a hole having a shape of a curved surface to accommodate the ball bearings as in the prior art, reducing mold cost, and shorten the production period.