A method and a system of manufacturing electric wires by ordering, possible to save the cost and materials, is provided. A system includes an order-receiving section, a manufacturing section and a coloring/cutting section. The order-receiving section receives orders of electric wires, and outputs a first datum of amount of electric wires DT1, informing a length of a monochromatic electric wire, and outputs a second datum of amount of electric wires DT2, informing lengths for respective colors of electric wires. The manufacturing section manufactures a monochromatic electric wire according to the first datum DT1 and conveys the electric wire to the coloring/cutting section. The coloring/cutting section colors and cuts the electric wire according to the second datum DT2.