Provided is a toner recycling device for an image forming apparatus, including a waste toner conveying screw which conveys waste toner collected out of a surface of a photosensitive drum to one side; a toner recycling means which is connected with the waste toner conveying screw to be rotated by rotation of waste toner conveying screw, filters a foreign substance out of the waste toner conveyed by the waste toner conveying screw, supplies the recycled toner from which the foreign substance is removed toward a developing unit, and discharges the foreign substance filtered out of the waste toner to an outside of a drum unit; and a collecting case which is integrally formed with the drum unit at one side of the drum unit to collect the foreign substance filtered by the toner recycling means, wherein the foreign substance like paper dust contained in the waste toner is filtered, and then the recycled toner is supplied again toward the developing unit, thus it is possible to prevent the quality of a printed image from being degraded.