The inventive device for producing a tire reinforcement comprises a guide (60) in which a thread (4) can slide. Said guide (60) is carried by an actuating unit (3). A guide ring (5) is arranged with respect to a main arm (31) in such a way that it passes through said ring during the cyclic motion thereof. The ring comprises a slot (54) in such a way that the thread is enabled to pass through. Thering (5) consists of a base (50), two sidewalls (51) connected to said base and disposes on both sides thereof, two deflectors (52), each deflector being connected to one of the sidewalls and arrangedon the end thereof which is opposite to the base. Said two deflectors are oriented towards each other and provided with a lip (53) on the ends thereof. Said lips are embodied in a similar and opposite shape and delimit the slot (54).