The invention relates to a vehicle headlight bulb comprising a bulb socket, an illuminant (2) arranged inside the bulb socket (1), and a base comprising a metallic sleeve (3) in which a sealed end (11) of the socket (1) is fixed. According to the invention, at least one of the narrow front sides (111) of the sealed end (11) of the socket (1) is provided with a serrated profiled element (1110) which extends in the longitudinal direction of the bulb and forms a latch connection with at least one locking plate (33) formed on the base sleeve (3).