A mechanical device is used for mounting and/or dismounting a laser nozzle on and/or from a nozzle mount of a laser processing machine for processing workpieces, especially metal sheets. The mechanical device includes a nozzle magazine having a nozzle holder support on which a nozzle holder for a laser nozzle is supported. In addition, the mechanical device has a support positioning drive by means of which the nozzle holder support is positionable together with the nozzle holder in a support positioning direction. A lifting device of the mechanical device serves to position the nozzle holder, when positioned in the support positioning direction in a lifting stand-by position, relative to the nozzle holder support in a positioning lifting direction extending perpendicular to the support positioning direction.