PURPOSE: To strengthen the resistance to damages from outside and prevent generation of a large amount of harmful gases and smoke at the time of burning by forming a bilayered coating composed of a mixture of mainly olefin-based resin having a prescribed oxygen index and tensile strength on the outer circumference of a cable.

CONSTITUTION: A coating having a bilayered structure composed of an inner layer of a mixture containing mainly olefin-based resin with an oxygen index of 27 or more and tensile strength of 0.7kgf/mm2 or more and an inorganic hydrate compound and an outer layer of a mixture containing olefin-based resin with oxygen index of 22 or more and tensile strength of 1.2kgf/mm2 or more and an inorganic hydrate compound, is formed on the outer circumference of a flame retardant cable. The thickness of the inner layer is 50-90% of the whole thickness. As the olefin-based resin, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, etc., are used. As the inorganic hydrate compounds, aluminum hydroxide, calcium hydroxide, hydromagnesites are used, and besides them, a lubricating agent, a pigment, a flame retarding agent, an antioxidant, and a cross-linking agent may be added.