A method for producing an elongated optical fiber element is disclosed. The method envolves preparing two optical fiber elements by removing their outer coating layers to expose bare glass fiber portions. The glass fiber portions are melt-joint together. A material which is chemically compatible with the removed outered layer is then molded about the joined bare glass portions. A thermoplastic resin is then extruded continuously over the molded material in order to form a single elongated optical fiber element. The bonding method produces a structure which can withstand bending stress exerted on the coated optical fiber and prevent the concentration of any stress in the bonded area.