To prevent propagation of adhering bacteria and reduce a gap on the side of a mask by plating the surface of a synthetic fiber with silver or by forming a mask by using a fiber with evaporated silver.

A fiber with silver is provided on the face contact side of a mask having a mask main body formed by folding a cloth piece several times to construct a mask 10. A fiber with silver and a cotton single yarn are plain- woven to form a face contact side 12. The fiber with silver is formed by electroless plating the surface of a nylon fiber with silver or by evaporating silver on the surface of the fiber in a vacuum. This may be a fiber formed by making silver adhere to the surface of a single yarn or a twisting obtained by twisting plural yarns, or a fiber formed by entangling a silver adhering yarn and a silver non-adhering yarn. The silver content of the nose and mouth contact parts is increased to heighen the shape retaining performance, so that the face adhesion of the mask 10 along the relief of the nose can be improved. Thus propagation of bacteria can be prevented, and the adhesion performance can be improved.