The utility model discloses an inclined to one side device is prevented to beam -pumping unit polished rod, including the packing box with wear to establish the polished rod in the packing box, be fixed with the bottom plate on the up end of packing box, be fixed with the montant on the up end of bottom plate, can be connected with the sliding sleeve on the montant with sliding from top to bottom,wear to be equipped with the bolt that is used for locking sliding sleeve and montant on the lateral wall of sliding sleeve, bolt and sliding sleeve threaded connection, the outside cover of polishedrod is equipped with the sleeve, be provided with the slide that a plurality of is circumference evenly distributed on the telescopic lateral wall, sliding connection has the steel ball in the slide,the interior tip department of slide is provided with the bell that can supply the steel ball part to wear out, the threaded connection of outer tip department of slide has the closing cap, be provided with the spring in the slide between closing cap and the steel ball, sleeve and sliding sleeve pass through the connecting rod and connect, the utility model provides a be rolling friction betweensteel ball and the polished rod to can effectively reduce the resistance of polished rod, the wearing and tearing that have effectively slowed down the polished rod have improved the life of polishedrod.