To produce an Al alloy for a screw cutting material having mechanical and physical properties similarly to the case in which Pb is contained by subjecting an Al alloy having a specified compsn. contg. no Pb to homogenizing heat treatment, thereafter executing cooling, cutting it into a billet, executing extrusion and thereafter subjecting the same to thermal-mechanical treatment.

An Al alloy contg. no Pb harmful to health, but contg. 0.10 to 0.7% Sn and 0.20 to 0.80% Bi and furthermore contg. specified amounts of Si, Fe, Cu, Mn, Mg, Cr, Zn, Ti or the like is melted. This ingot is heated at 482 to 571°C at least for 1hr, is subjected to homogenizing treatment, is thereafter cooled to a room temp. and is cut into a billet, which is reheated to about 316°C and is extruded. Successively, it is subjected to cold working and is thereafter subjected to thermal-mechanical treatment composed of solution heat treatment at 499 to 554°C for about 0.5 to 2hr, swift quenching to a room temp. and cold working and artificial aging treatment of heating at 149 to 193°C for 4 to 12hr to produce the Al alloy for a screw cutting material substantially contg. no Pb harmful to health.