A carried material is carried only on a surface of nano-fibers. It includes a raw material liquid spray step that sprays raw material liquid, which is a raw material of nano-fibers, into a space, a raw material liquid electrically charging step, which applies an electric charge to the raw material liquid and makes the raw material liquid electrically charged, a nano-fiber manufacturing step that manufactures the nano-fibers by having the electrically charged and sprayed raw material liquid explode electrostatically, a carried material electrically charging step that electrically charges a carried material carried on the nano-fibers with a polarity opposite to a polarity of the electrically charged nano-fibers, and a mixing step that mixes the manufactured nano-fibers and the electrically charged carried material in a space.