Abstract: In a metal zipper, each metal tooth has a mounting hole located on one end of the base thereof, two first engagement portions and two second engagement portions formed integral with the base at two opposite sides of the mounting hole for engaging into the top and bottom sides of the inner edge of the respective zipper tape to deform the respective inner edge during installation so that engagement between the zipper tape and the metal tooth is enhanced, avoiding vibration of the metal tooth relative to the zipper tape during operation of the metal zipper and prolonging the lifespan of the metal zipper. Further, each metal tooth has a concave surface portion formed in the protruding tooth head thereof so that less friction is produced when the metal zipper is closed or opened.