The invention provides a plated fiber, a carbon fiber, a wire harness and a plating method. The plated fiber is obtained by applying a metal plating onto a fiber having an elongation percentage whichis more than or equal to 1% and less than or equal to 10%. An elongation percentage of the metal plating is higher than the elongation percentage of the fiber. A carbon fiber wherein the surface oxygen amount as a value obtained by dividing an O1S peak intensity measured by X-ray photoelectron spectroscopy by a C1S peak intensity measured by the spectroscopy is more than or equal to 0.097 and lessthan or equal to 0.138.