The invention relates to a dust mask mainly used in an industrial field. The dust mask comprises a three-dimensional filter body and a three-dimensional orthosis arranged inside the filter body in a detachable mode, in particular, in the dust mask, the orthosis comprises a supporting body, a nose bridge extrusion tool and pad sponge, the supporting body is composed of a non-woven fabric, the non-woven fabric is harder than the filter body in material, has a loose breathable tissue structure, and can absorb moisture generated by respiration of a user, the nose bridge extrusion tool is transversely attached to the upper end of the outer side of the supporting body, is covered with the filter body, and can perform bending adjustment, and the pad sponge is transversely attached to the position, corresponding to the extrusion tool, of the upper end of the inner surface of the supporting body. According to the dust mask, the adhesion force and the wearing feeling of the nose portion of the user can be improved, and the moisture generated by respiration can be easily treated.