PURPOSE: A manhole duct is provided to prevent a bolt and nut which is fixed and coupled in a process installing a manhole duct cover to a manhole to be separated from the manhole duct cover. CONSTITUTION: A manhole duct cover(100) comprises a connecting part(110) and an insertion part(120). The insertion part is inserted inside a manhole duct. The insertion part is used as a body of the manhole duct cover formed as a cylindrical shape. The connecting part is connected to one side of the insertion part. The connecting part is fixed and coupled with the entrance of the manhole duct by a fixing device. The connecting part comprises a joint hole(111). The connecting part has a closed one side and the other side which is combined with the one side of the insertion part.
