A hard disc drive cover-integrated gasket, which comprises a metallic cover and a packing material integrated with the metallic cover, the packing material being a molding material from a mixture comprising 100 parts by weight of EPDM or a blend of EPDM and polystyrene type thermoplastic elastomer, 10-100 parts by weight of polypropylene type resin, 20-130 parts by weight of a plasticizer and 0.1-10 parts by weight of a cross-linking agent is easy to fabricate and has distinguished characteristics as low outgassing characteristics, low hardness, good sealability at elevated temperatures, etc.