Abstract: A lance in a converter is supported at a first part thereof on a gimbal mechanism supported on a bridge supported on rotation devices supported on a lance carriage above the converter and operating to drive the bridge and the first part of the lance to undergo a revolutionary motion, and is held at a second part thereof below the first part against horizontal movement by another bearing device, whereby the lance is driven in gyratory motion about the center of the second part as a central node, the radius and speed of gyration of the working end of the lance being adjustable. Pertinent parts of the lance carriage, which can be raised and lowered in guided vertical movement by a hoisting device, are provided with cutout recesses into which the lance in vertical state at the time of installation can be placed by being moved sidewise in horizontal movement, whereby the installation and removal of the lance is greatly facilitated.