Disclosed herein is a lead pin for a package substrate.The lead pin for the package substrate includes a cylindrical connection pin; and a head part that is formed on one end of the connection pin and has a convex round part formed on the lower end of the head part, having a step part. When the lead pin for the package substrate is mounted on the package substrate, the bulge phenomenon of a solder paste that surrounds the head part and is melted is prevented by a flange part, thereby making it possible to prevent the connection pin from being polluted and to improve a contact defect such as a short defect or the like when coupling a socket.