Resin composition, insulated electric wire, cable and method of manufacturing insulated electric wire

The invention provides a resin composition which has both an improved crush resistance in an uncross-linked state and an improved degree of cross linkage at the time of cross linkage, an insulated electric wire, a cable and a method of manufacturing the insulated electric wire. The insulated electric wire includes a conductor and an insulating layer arranged in periphery of the conductor. The insulating layer is made of a resin composition containing a base polymer and a metallic hydroxide. The base polymer contains ethylene-vinyl acetate copolymer and ethylene-[alpha]-olefin copolymer. The [alpha]-olefin is a non-polarized monomer, its melting point is equal to or lower than 70 DEG C. A vinyl-acetate total content of the base polymer is equal to or less than 19 mass %. The resin composition contains the ethylene-[alpha]-olefin copolymer, a content of which is equal to or more than 20 parts by mass and equal to or less than 70 parts by mass per 100 parts by mass of the base polymer, and contains the metallic