The utility model discloses a disposable dust mask, including gauze mask main part top facing, expose bridge of the nose strip, bridge of the nose sealing strip, tensile folding strip, hangers rope, its characterized in that, the top edge of gauze mask main part top facing is provided with and exposes bridge of the nose strip and trilateral mobilizable bridge of the nose sealing strip, and the roof beam sealing strip does not receive tensile influence of hangers rope under the extrusion that exposes bridge of the nose strip to deadend bridge of the nose both sides. The folding tensile gauze mask in disposable plane of rationally having solved prior art can not seal, problem that the gas leakage phenomenon is very serious, protecting effect is poor. The utility model discloses to overlap and dig on first bridge of the nose sealing strip of gauze mask main part top facing is to gauze mask main part top facing upper end edge, and overlap at gauze mask main part top facing upper end edge, when wearing, bridge of the nose sealing strip is in lower tight bridge of the nose both sides of the extrusion that exposes bridge of the nose strip, improves the adaptation ability of gauze mask greatly, has overcome the not enough of prior art.