The present invention discloses a drill head structure for dental handpiece comprising a drill head main body, a screw nut and an adjusting ring. The drill head main body may be attached to a driving end of a dental handpiece so that the drill head main body may be driven by the dental handpiece to rotate at high speed. On the drill head main body is disposed a thread section. The screw nut is a hexagonal nut to be screwed to the thread section of the drill head main body. The adjustment ring has predetermined ring widths, and at a center thereof is disposed a hexagonal screw nut indent for the screw nut to be fitted into it. At a center of the adjustment ring is also disposed a threaded hole to be screwed to the foregoing thread section. The dental bone drill structure provided according to the present invention may achieve the purpose of controlling the drilling depth to which the drill head goes in and determine the drilling position.
