A new type of bone fastener is proposed, which is suitable for implantation either in a fractured shinbone (tibia) or a fractured thighbone (femur). The bone fastener includes an elongated steel tube having a bent tail portion, a middle portion, and a frontal portion, with a plurality of screw holes being formed in a non-parallel manner in the bent tail portion and the frontal portion. Further, a set of bolts are selectively screwed to the screw holes depending on the case of either a shinbone fracture or a thighbone fracture so as to secure the fractured part together. Since the screw holes and the bolts are oriented in a non-parallel manner, the bone fastener can be hardly loosened off position when the user moves on foot at fast paces, thus providing a better fastening effect than the prior art.