The apparatus for manufacturing a reinforcement for a tire comprises an eyelet 60 through which the cord 4 can slip; the eyelet 60 is carried by a drive mechanism 3. A guide ring 5 is positioned relative to a main arm 31 in such a manner that this passes through the ring during its cyclical movement. The ring comprises a slot 54 through which the cord passes. The ring 5 comprises a base 50, two lateral walls 51 which are rigidly connected to the base and which are disposed on either side thereof, two deflectors 52 each rigidly connected to one of the lateral partition walls disposed at the end thereof opposite the base, the two deflectors being oriented towards one another and each ending with a lip 53, the lips being of similar and opposite shapes, the slot 54 being defined by the lips of the deflectors.