PURPOSE: To provide high breaking-load characteristics and improve high-frequency characteristics by providing a conductive layer for an outer layer of tension member made from a ceramic fiber and an insulation layer for the outer-most layer of the conductive layer.

CONSTITUTION: A tension member 1 is formed of a ceramic fiber of alumina- silica but the tensile strength of the fiber is within the range of 75 to 500kg f/mm2 and the diameter thereof is within the range of 0.5 to 20μm. A conductive layer 2 is disposed on the outside of the tension member 1 and is formed with the covering of aluminum, copper, silver, gold, alloy thereof or the like made by a fusion covering method, a plating method or the like. An insulation layer 3 is disposed on the outside of the conductive layer 2 and is formed with the enamel coating of ordinary polyurethane, polyvinylformal or the like painted and baked. Thereby, inspire of its very small diameter, an insulation wire with high breaking tensile load may be obtained.