An optical connector (1, 1') comprising: an optical fiber (F, F') including a glass fiber and a resin coating surrounding the glass fiber; a ferrule (10, 10') having a flange outside the ferrule (10, 10') and a through-hole inside the ferrule (10, 10'), the ferrule (10, 10') holding, in the through-hole, a portion of the glass fiber exposed from the resin coating at an end of the optical fiber (F, F'); a plug frame (20, 20') accommodating the ferrule (10, 10'); and an elastic member abutting the flange and biasing the ferrule (10, 10') forward in a direction of an axis of the through-hole, wherein the flange has a flat surface on an outer periphery thereof, and the plug frame (20, 20') has a guide surface configured to unrotatably align the ferrule (10, 10') biased by the elastic member at a predetermined position in contact with the flat surface of the flange, and when the ferrule (10, 10') is moved rearward in the direction of the axis of the through-hole relative to the predetermined position, the flat surface is separated from the guide surface to bring the ferrule (10, 10') into a floating state relative to the plug frame (20, 20'); wherein the flat surface is a face parallel to the axis of the through-hole, the guide surface is a face in an inner peripheral surface of the plug frame (20, 20') and parallel to a biasing direction of the elastic member, and wherein the plug frame (20, 20') has a tapered surface in the inner peripheral surface of the plug frame (20, 20') at a position opposite the guide surface such that an inner space becomes gradually narrower forward in the direction of the axis of the through-hole; characterised in that the flange is held between the tapered surface and the guide surface when the flat surface is in contact with the guide surface at the predetermined position. an optical fiber (F, F') including a glass fiber and a resin coating surrounding the glass fiber; a ferrule (10, 10') having a flange outside the ferrule (10, 10') and a through-hole inside the ferrule (10, 10'), the ferrule (10, 10') holding, in the through-hole, a portion of the glass fiber exposed from the resin coating at an end of the optical fiber (F, F'); a plug frame (20, 20') accommodating the ferrule (10, 10'); and an elastic member abutting the flange and biasing the ferrule (10, 10') forward in a direction of an axis of the through-hole, wherein the flange has a flat surface on an outer periphery thereof, and the plug frame (20, 20') has a guide surface configured to unrotatably align the ferrule (10, 10') biased by the elastic member at a predetermined position in contact with the flat surface of the flange, and when the ferrule (10, 10') is moved rearward in the direction of the axis of the through-hole relative to the predetermined position, the flat surface is separated from the guide surface to bring the ferrule (10, 10') into a floating state relative to the plug frame (20, 20'); wherein the flat surface is a face parallel to the axis of the through-hole, the guide surface is a face in an inner peripheral surface of the plug frame (20, 20') and parallel to a biasing direction of the elastic member, and wherein the plug frame (20, 20') has a tapered surface in the inner peripheral surface of the plug frame (20, 20') at a position opposite the guide surface such that an inner space becomes gradually narrower forward in the direction of the axis of the through-hole; characterised in that the flange is held between the tapered surface and the guide surface when the flat surface is in contact with the guide surface at the predetermined position.