A crosslinkable halogen-free resin composition includes a polymer blend, and a metal hydroxide mixed in an amount of 120 to 200 parts by mass per 100 parts by mass of the polymer blend. The polymer blend includes a high-density polyethylene, 30 to 50 parts by mass of an ethylene-acrylic ester-maleic anhydride terpolymer, 5 to 20 parts by mass of a maleic anhydride modified ethylene-α-olefin copolymer and 10 to 30 parts by mass of an ethylene-vinyl acetate copolymer.