Abstract: A multi-purpose writing instrument having a series of writing tips for various uses includes a hollow tubular mounting having a mounting wall surrounding a through hole, an upper end of the mounting wall forming a mounting step with inner threads. A lower section of the mounting wall has a tapered configuration which extends downwardly to form a straight section having a tip hole. An outer surface of the lower section of the mounting wall is cut horizontally and then vertically to form an insert surface and an insert step which is, in turn, joined to a plurality of outer threads before extending to the tapered end. The outer diameter of the insert surface corresponds to the diameter of the mounting hole while the external and internal holes engage each other. The writing tip has a size matching that of the tip hole so that it may fit firmly into the tip hole.