PURPOSE: To ensure a good magnetic field uniformity and supply a higher output by returning symmetrically a wound stripe toward a conductor wire for the wound stripe guided toward an end surface viewed from a coil side opposite to a power supply member viewed axially.

CONSTITUTION: A wound stripe division 9 with a substantially semicircle is extended from a power supply conductor wire 7, to which division an axially short connection division 10 guided vertically upwardly is connected and which is transferred to another substantially semicircle wound stripe division 11 extending in opposite winding direction to that of the wound stripe division 9. A short connection division 12 is connected with the end portion, and a wound stripe division 13 forming a substantially circle is guided to a connection division 14 extending parallely downwardly. To this there are connected a wound stripe division 15 of a semicircle symmetrical with respect to the wound stripe division 11, a connection division 16 extending downwardly, and a wound stripe division 17 forming a substantially circle and guided to a return conductor wire 8. Hereby, a magnetic field symmetrical with respect to a central axis is formed in a coil 5 to arrest side displacement of a molten stripe stream.