PURPOSE: To produce a titled electric wire which has large crystal grains and good sound by one process, by producing an ingot of a unidirectionally solidified copper by using a casting mold which projects at one end into a molten copper bath and is in contact at the other end with a cooling structural body and subjecting the ingot to a drawing treatment.

CONSTITUTION: The end of a pure copper rod having a prescribed outside diameter is positioned to the inside of the molten copper 1 at a prescribed length from the supply side thereof in the graphite casting mold 6 having the hole of a prescribed diameter mounted to the side wall in the bottom of a melting furnace 2. The molten oxygen-free copper is put into the furnace 2 and is held at a prescribed temp. Water is passed to the cooling structural body 5 installed to the side opposite from the supply side of the molten copper in the casting mold to provide the solidification position of the pure copper on the molten copper supply side in the casting mold 6. Gaseous N2 is introduced through an introducing port 4 into the mold 6 and is ejected into the molten copper 1 so as to cover the surface of a casting rod 3, by which the molten copper 1 is stirred. The solidified rod is continuously drawn by pinch rolls 7 to produce the unidirectionally solidified matter. Such copper is subjected to the drawing treatment, by which the objective electric wire for audio use is obtd.