A method of producing a wired circuit board that can prevent the
electrostatic damage of the components mounted on the wired circuit board
effectively, while preventing operation errors of the device caused by
the static electricity. After a thin metal film is formed over an entire
area of a front side of an insulating cover layer and an entire surface
of a conductor layer at a terminal portion thereof by sputtering, a metal
oxide layer is formed on the thin metal layer by an oxidation-by-heating
method or by the sputtering. According to this method, since the
semi-conductor layer comprising the thin metal film and the metal oxide
layer is formed on the surface of the insulating cover layer, the
electrostatic damage of the components mounted on the wired circuit board
can be prevented effectively. Also, the operation errors of the device
caused by the construction wherein only the thin metal film is formed can
also be prevented effectively. Further, the semi-conductor layer having a
uniform surface resistance which falls within a preferable range can be
formed, as compared with the construction wherein the metal oxide layer
is formed directly on the insulating cover layer by the reactive
sputtering or by the sputtering using the metallic oxide target.