Replace a subset of the frame, and the remainder continued to use because the edge of the replacement with the filter main body to be reduced is that, formed into a plate shape is possible in the cost, protective net of the pair which is installed on both sides of the filter body and the filter body and the protective net surrounding made of superior materials corrosion resistance for the simple frame, a strength is excellent and the moisture and contaminants is fixed is made by using the first supporting frame, the same material as the first support frame which surrounds one edge of the simple frame fixed It is to provide an air purifying filter for the mobile communication base station including a second support frame for supporting slidably surrounding the rest of the edges except for one corner of the simple frame. Mobile communication base stations, filters, air purification, pollution, replace the frame