A vertical mill gearbox includes a drive shaft mounted in a casing for rotation about a rotation axis, and an intermediate shaft configured as a hollow shaft and mounted in the casing for rotation about a vertical second rotation axis. The intermediate shaft has a bevel gear meshing with a bevel-gear pinion of the drive shaft. A torsion shaft is received in fixed rotative engagement with the intermediate shaft and sized to extend beyond the intermediate shaft to define a projecting section to which a sun gear rotatably driven via the intermediate shaft is fixed. A planet carrier is mounted in the casing for rotation about the second rotation axis and rotatably supports an internal gear having an internal tooth system. Mounted to the planet carrier is a rotatable planet gear which meshes with the sun gear and with the internal tooth system of the internal gear.