A driver tool for a spinal implant having an implant body and an anchoring screw portion, and a nut member screwed onto a head portion of the implant body and having an upper wall formed with a tool engagement groov. The driver tool includes an elongated shaft, and a tubular tool end having substantially the same diameter as that of the nut member. The tubular tool end has an engaging segment engageable with the engagement groove formed on the upper wall of the nut member.