Abstract: A power cable 1 according to the present invention contains a propylene-based resin in a specific range as an insulating layer 13, and has a specific relationship between the cooling rate X at the time of manufacturing the interface portion in the insulating layer 13 with an inner semiconductive layer 12 and the cooling rate Y at the time of manufacturing the central portion of the insulating layer 13. Thus, not only the surface of the insulating layer 13 but also the inside of the insulating layer 13, the interface portion in the insulating layer 13 with the inner semiconductive layer 12, and the inside thereof are reliably cooled and cured. Therefore, the metal conductor 11 is not displaced from the center of the power cable 1 due to its own weight, and uneven thickness is less likely to occur.

Abstract: A method of producing an optical fiber, containing: (a) a resin application step of applying an ultraviolet curable resin, onto an outer circumference of an optical fiber; (b) a heating step of heating the ultraviolet curable resin; and (c) a light irradiation step of irradiating the ultraviolet curable resin with ultraviolet light emitted from a semiconductor light emitting element, in a state in which the ultraviolet curable resin is heated, to cure the ultraviolet curable resin into a coating resin.