PURPOSE: To provide good concentricity to the outside diameter of a ferrule by forming a through-hole of the inside diameter equal to the diameter of an optical fiber to the central of a cylindrical ferrule member consisting of a metal by a deposited metal.

CONSTITUTION: A wire rod 6 consisting of an org. material having the outside diameter (d) nearly the same as the outside diameter of the optical fiber strand is supported at the center of the through-hole 11 and the ferrule 1 is connected in this state to one side of a power supply 54 for plating, then a plating treatment is executed, by which the deposited metal 17 is uniformly stuck on the inside surface of the through-hole 11 of the ferrule. The thickness of the metal 17 increases when the plating treatment is further continued. The supply of the plating liquid to the deposited surface is interrupted and the plating ends at the point of the time when a spacing 18 is filled. The ferrule member 1' is taken out of a plating cell and the wire rod 6 and insulating film 16 are removed by a suitable method such as dissolving or burning. The ferrule formed with the fiber hole 12 having the desired inside diameter (d) with the good concentricity with the outside circumference 14 is thereby obtd.