Abstract: A device for retaining a wire-like optical wave-guide for an optical connector includes a cylindrical plug made of an elastic material for gripping the outer peripheral surfaces of a wire-like optical wave-guide with at least one end portion of the plug, having a predetermined length, being divided into a plurality of portions in a circumferential direction. The cylindrical plug has an expanded form in which a distance from an axis of the plug to each of the divided portions gradually increases toward the one end of the plug, with a tightening member pressing a vicinity of a free end of the cylindrical plug, which is in a state where the wire-like optical wave-guide is passed through the plug along the axis of the plug so as to allow the wire-like optical wave-guide to be retained by the cylindrical plug, in a direction substantially perpendicular to the axis of the plug from the outside of the plug.