An optical fiber placement surface has formed thereon width-directional position restricting sections for partially restricting the position of an optical fiber ribbon in a width direction perpendicular to the axial direction of the optical fiber ribbon. A portion other than the width-directional position restricting sections serves as a width-directional position non-restricting section that does not restrict the position of the optical fiber ribbon in the direction perpendicular to the axial direction of the optical fiber ribbon. A pressing member is formed at a portion corresponding to the width-directional position non-restricting section. On the other hand, the pressing member is not formed at positions corresponding to the width-directional positional restricting sections. Thus, the optical fiber ribbon is not pressed at the width-directional positional restricting sections. Portions at which the optical fiber ribbon is not pressed by the pressing member are defined as non-main pressing sections.