Optical fiber and optical fiber ribbon

No peeling color at single core separated from the optical fiber ribbon, and curing of the resin coating layer provides sufficient optical fiber. Optical fiber 10 includes a glass fiber 13, and a resin coating layer 16 covering the outer periphery of the glass fiber 13, the resin coating layer 16 has a colored layer of a thickness of not less than 10 [mu] m, the resin in the coating layer 16 contains from 0.06 to 1.8 wt% of the titanium element, the optical fiber ribbon 20, the optical fiber 10 is more parallel, the plurality of optical fibers 10 is connected It is connected by wood 21.