Abstract: An improved structure of a screw mounting device comprising a machine body, a machine tubing, a controlling module and a retractable adjusting device located at one lateral side of the machine body, the end face of the front end of the machine body being a sloping side to allow a sliding wheel of the controlling module to urge against the sliding, the controlling module comprising a guiding rod, the sliding wheel and a cavity body and the controlling module located at the side of a screw insertion slot module, characterized in that the lateral side of the sliding rod is extended to provide a shaped holding block, and the holding block is appropriately mounted at a recess located at the bottom section of the screw-pushing plate, the sliding wheel is pivotally mounted at the top section of the guiding rod, and the bottom section of the guiding rod is provided with a spring within the cavity body, thereby when the sliding wheel urgingly slides together with the sloping side, the guiding block is simultaneously m