A sealing device used for preventing the risk of explosion or fire caused by the electrostatic spark occurring at the sealing section of doorway of a partition using flammable gases liable to cause explosion or fire in a continuous annealing furnace for conducting bright annealing or nonoxidative annealing of metal strips, continuous coating equipment, and the like, and for preventing the surface of a strip from being scuffed or scratched. The device is provided in the sealing section and comprises a combination of metallic sealing pieces (16), elastic pads (17) provided on the surface of each piece (16), and elastic rotating rolls (18) pressed against a metal strip (1) and the pads (17). The pad (17) has a surface resistivity of 10 -10 OMEGA .cm and is made of a carbon-containing fiber, a chemical fiber made from polypyrrole, which is a conductive polymer with a conjugated electron system, a fiber prepared by treating an acrylic fiber with a copper (II) compound and a sulfur compound, or a conductive nonwoven fabric mainly comprising these fibers.