The present invention relates to a method for manufacturing a stamper for injection molding, and more particularly, to a method for manufacturing a stamper for injection molding which can prevent a scratch from forming thereon and has an excellent durability owing to high hardness even after manufacturing of the metal stamper with micro patterns formed thereon is finished. The method for manufacturing a stamper for injection molding includes a pattern forming step for forming a predetermined micro pattern on a substrate, a metal plating step for making metal plating on the substrate to form a stamper having the micro pattern transcribed thereto, a stamper separating step for separating the stamper of the metal plating from the substrate, and a protective layer coating step for coating a protective layer on the stamper for maintaining a mirror surface.