In a method for producing an optical fiber ribbon, a plurality of coated optical fibers is fed out so that the plurality of coated optical fibers are arranged in a plane in a concentrator. A ribbon matrix composed of ultraviolet-curing resin is applied onto the plurality of coated optical fibers in a coater. Ultraviolet rays is radiated to cure the ribbon matrix. The plurality of coated optical fibers are arranged at intervals in a plane in the concentrator. <IMAGE>