Abstract: The present invention relates to a four-sided dustproof mask including: an upper filter adapted to surround a wearer's nose area; a lower filter adapted to surround the wearer's chin area; and a protruded center filter adapted to attach the upper filter and the lower filter thereto in such a manner as to make the both ends of the upper filter and the lower filter correspond to center points formed at the both ends of a curved folding line dividing the protruded center filter into two sides, the curved folding line having a straight line portion having a predetermined length protrudedly extended from the center points thereof, whereby while the upper filter and the lower filter are being developed, the protruded center filter is protruded to a dome-like shape.