A connection device for a fluid line, which has a connection unit that can be fixed in an internally threaded fastening opening of a carrier component by means of an externally threaded section of a fastening element, said threaded section consisting of a rubber elastic material. An insertion opening extends through the connection unit and the fluid line to be connected can be inserted therein so that it projects through an annular retaining element fixed in the fastening element and is retained. The external thread of the threaded section is surrounded by at least one annular outer sealing bead which is an integral part of the threaded section, said sealing bead improving the sealing with respect to the internal thread.