There are provided an electric cable coloring method and an electric cable coloring device capable of performing a predetermined marking on an electric cable even if the moving speed of the electric cable is changed. The electric cable coloring device applies a predetermined amount of liquid coloring material in droplets toward the external surface of the electric cable so as to color the electric cable. The coloring material has viscosity not smaller than 0.3 mPas and not greater than 4.5 mPas.