In manufacturing slide fasteners, especially fastener elements, an elongated wire of a generally Y-shape cross section with attaching legs shaped into a generally C form by rolling, is supplied intermittently at a predetermined pitch and is then cut into slices of element blanks having a predetermined thickness, and a protuberance is formed on the coupling head of each of the successive element blanks. Then, the generally C-shape attaching legs are calked from opposite sides to mount the fastener elements on a fastener tape and, at the same time, the generally right-angled cut edges of the attaching legs are shaped into a smooth arcuate profile as pressed by a calking surface of a calking punch.