The invention relates to a method and device for fixing a faucet to a mounting (1), such as a worktop or a sinktop. A fixing collar (2) is fastened to the top surface of a mounting by turning from above one or more set screws (3) extending from the fixing collar (2) over a distance below a bottom surface of the worktop. Turning of the screw is used for raising a clamping claw (4), which is in engagement with the threading of said set screw and which is steered by means of a guide (5) extending downward from the fixing collar and used for disallowing a rotation of the clamping claw (4) along with the set screw (3). The bottom end of a faucet body (10) or its extension is fastened around the fixing collar (2) by expanding the fixing collar (2) by an actuation means, such as a screw (8).