A car headlight lamp having a lamp envelope (1), which is closed by seals (2) through which current lead-in members (3,4) are passed and is secured by a holding member to a socket (17), the holding member having a dipping cap (12), which at least partly surrounds the lamp envelope and is connected to a current lead-in member (4) of the lamp envelope. The socket (17) has an outwardly projecting cylindrical flange bush (24) for receiving the lamp envelope (1) and the lamp envelope has a tubular prolongation (6), onto which a clamping sleeve (7) is slipped, which consists of a cylindrical sleeve body (8), which has an outer flange (9) secured to the flange bush and several inwardly directed resilient tongues (10), which bear on the prolongation of the envelope. The dipping cap (12) is secured to the clamping sleeve (7).