The coupling device (40) comprises a holding fixture (30) being designed to be mechanically coupled to the fuel rail and comprising a through hole (42) extending between a first surface (44) and a second surface (46), the second surface (46) opposing the first surface (44) and being arranged and designed to face the cylinder head. Furthermore the coupling device (40) comprises a fastening element (48) being designed to be fixedly coupled to the cylinder head. The fastening element (48) comprises a head portion (50) and a shank portion (52). The head portion (50) faces the first surface (44) of the holding fixture (30) and the shank portion (52) is being partially arranged in the through hole (42) and is designed to be in engagement with the cylinder head. In addition the coupling device (40) comprises a retaining element (64) being arranged inside the through hole (42), being coupled with the holding fixture (30), comprising in a given latch area (65) a cross-section restriction and being in engagement with the shank portion (52) at least in this latch area (65) . The retaining element (64) is formed as a one-piece unit.