PURPOSE: To provide a composite soldering material excellent in the ductility at high temperature and excellent in the cold machinability as the soldering material to join the parts of a semi-conductor device accompanying the heat generation.

CONSTITUTION: The soldering material having the composition consisting of, by weight, 5-15% Sb, 2-15% Ag, and the balance substantially Sn with inevitable impurities is melted in the inert atmosphere, and cast to manufacture the ingot. This ingot is extruded, and rolled or cold machined by the drawing to manufacture the tape or wire of the prescribed shape and dimension.