Provided is an optical fiber ribbon capable of achieving higher density and reduction in diameter and accurately placing optical fibers in V-shape grooves in a fusion machine without failure. The optical fiber ribbon 1 includes three or more of optical fibers 2 arranged in parallel and connecting portions 3 connecting adjacent two optical fibers 2 together, the connecting portions 3 being intermittently provided in each of a ribbon longitudinal direction and a ribbon width direction. The connecting portions 3 are each formed in such a manner as to fill resin into a gap S formed between adjacent two optical fibers 2, and both surfaces of the respective connecting portions 3 are each formed into a recess having a concave shape curved toward a center of the gap S to separate from lines 4,5 each connecting contact points of the optical fibers 2 when being placed on a horizontal surface.