Provided are the high tensile nonmagnetic stainless steel wire for an low loss overhead electric conductor, the low loss overhead electric conductor using the high tensile nonmagnetic stainless steel wire as its core, and a manufacturing method of them respectively. The high tensile nonmagnetic stainless steel wire reduces a core loss and eddy current loss and minimizes effective electric resistance of the conductor by using the nonmagnetic stainless steel wire, that is a non-magnetic material, rather than a high carbon steel wire, that is a strong magnetic material. In addition, an overall power transmission loss is minimized by strengthening the tensile strength of and reducing a sectional area of the steel wire, making an aluminium-welded layer thicker, and increasing the sectional area of an aluminium conductor.