a diving mask includes a nose cover and a valve seat of a drainage mechanism having a check valve formed in the vicinity of the nose cover . the nose cover and the value seat are formed from an elastic material which is integral with a soft elastic material forming the nose cover . in the vicinity of the valve seat , an annular member formed from a plastic material plastics having a hardness and deformation - resistance both higher than those of the elastic material forming the valve seat is embedded in a bottom of the nose cover so as to extend along the valve seat .