Activated-carbon filter box capable of being used as protective mask

The utility model relates to a respiratory filter, in particular to an activated-carbon filter box capable of being used as a protective mask. A casing containing activated-carbon filter element is used as a main unit of the activated-carbon filter box and consists of a casing base and a filter box cover which is detachably connected with the casing base, a joint communicated with the protective mask fixedly is arranged at the bottom of the casing base, and at least one hole is arranged on the top wall of the filter box cover. The activated-carbon filter box has the advantages that an external compressed air source can be used directly so that affection of the air source on construction site is avoided; the activated-carbon filter element can be changed independently so that cost can be saved; and the activated-carbon filter box can be used as a general protective mask or general dustproof mask after an air pipeline component is removed, a seal cap is detached and different activated-carbon filter element or