PURPOSE: To easily manufacture a back-notched peg, and to reduce its cost, by notching the surface of a peg by use of a cemented carbide cutting tool, and making a back-notched projection.

CONSTITUTION: A part of the surface of a peg 2 is notched by use of a cemented carbide cutting tool 1, etc., the part of the surface of the peg 2 is raised, and a back-notched projection is provided on the peg 2. According to said constitution, a back-notched peg can be manufactured very easily, and such a defect as is broken easily is removed.