PURPOSE: To eliminate corona discharge so as to prevent corona noise by forming a hydrophilic porous film on a surface of an element wire or a stranded wire.

CONSTITUTION: A hydrophilic porous film 22 is formed on the outside periphery of a single wire 21, at least whose outermost layer part is made of an Mg containing Al alloy, and a stranded wire 1 containing this single wire at least as a part of its element wires constitutes the cable. Formation of such a hydrophilic porous film 22 can be conducted in a batch process or in a process wherein a wire material to be processed is continuously supplied so as to be continuously fed to respective processes. Accordingly, even when a rain drop sticks to the cable it is absorbed by the hydrophilic porous film 22 in the surface thereof to smooth the surface so as to inhibit corona discharge and prevent generation of corona noise.