Abstract: According to the present invention, there is provided, at low cost, a thread/yarn for making it possible to easily determine whether a product is a genuine product or a forgery/imitation product, thereby suppressing the manufacture and marketing of forgery/imitation products. This forgery-preventing thread/yarn is formed by making use of a film comprising abase sheet and letters or images printed on the base sheet, the film being slit to have a width of 0.15 mm˜0.75 mm. A thread, yarn or a flat thread representing a genuine product can be cheaply manufactured since it can be obtained by simply slitting a film to a width of 0.15 mm˜0.75 mm. Further, it is possible to easily determine whether a product is a genuine product or a forgery/imitation.

Abstract: According to the present invention, there is provided, at low cost, a thread/yarn for making it possible to easily determine whether a product is a genuine product or a forgery/imitation product, thereby suppressing the manufacture and marketing of forgery/imitation products. This forgery-preventing thread/yarn is formed by making use of a film comprising abase sheet and letters or images printed on the base sheet, the film being slit to have a width of 0.15 mm˜0.75 mm. A thread, yarn or a flat thread representing a genuine product can be cheaply manufactured since it can be obtained by simply slitting a film to a width of 0.15 mm˜0.75 mm. Further, it is possible to easily determine whether a product is a genuine product or a forgery/imitation.