An organic cotton mask gentle to the skin, made with gauze-woven organic cotton. Silver thread μ-func (a coined word that combines “μ,” which represents 1/1000mm and “function”), which is drawing attention for its anti-bacterial, deodorizing and anti-static effects, is interwoven into the weft thread for the part that guards the mouth. The gauze mask keeps eyeglasses from fogging while preventing breathing difficulties and ear pain, which are the weaknesses of a normal masks. The string of the mask is tied in a special way so as to enable easy adjustment while avoiding ear pain. In addition, unlike conventional masks, this organic cotton mask is eco-friendly, as it is washable and can be used many times, which enhances its product value. Using cotton fabrics of certified Imabari towel products, the masks are dyed with subtle colors of plants and true indigo (hon-aizome) while food additives such as alum are used for dye mordant to ensure safety.