A vacuum mechanical rotation-transmitting apparatus is disposed on a hollow member that defines a vacuum chamber. The apparatus includes an input shaft assembly, an outer shaft assembly extending into the input shaft assembly and the vacuum chamber, a spacer member disposed between the input and output shaft assemblies, a plurality of first magnetic units disposed on the input shaft assembly, and a plurality of second magnetic units disposed on the output shaft assembly. A magnetic attractive force is produced between the first and second magnetic units to allow for co-rotation of the output shaft assembly with the input shaft assembly.