Optical fiber hole forming pins configured to form optical fiber holding holes each have a first portion located adjacent to a first end surface and a second portion located adjacent to a second end surface and larger in diameter than the first portion. At least one of the plurality of optical fiber hole forming pins is different from the other optical fiber hole forming pins in position, in a first direction, of a step portion located at a boundary between the first portion configured to form a small diameter portion of each of the optical fiber holding holes and the second portion configured to form a large diameter portion of each of the optical fiber holding holes.