A coupling device for mechanically coupling a fuel rail to a cylinder head of a combustion engine comprises a fuel injector cup designed to be hydraulically and mechanically coupled to the fuel rail and comprising a through hole extending between a first surface and a second surface of the fuel injector cup, the second surface arranged to face the cylinder head, and a fastening element designed to be fixedly coupled to the cylinder head, the fastening element comprising a head portion facing the first surface of the fuel injector cup and a shank portion partially arranged in the through hole and designed to be in engagement with the cylinder head. The coupling device comprises a first spring element arranged axially between the head portion and the first surface of the fuel injector cup, and a second spring element facing the second surface of the fuel injector cup and arrangeable axially between the second surface of the fuel injector cup and the cylinder head.