Abstract: A device for performing friction and wear tests inside a closed high-pressure autoclave under additional surrounding high pressure adjustable from the outside, wherein a test element arranged inside the autoclave is rotated by means of a driving shaft passed in a pressure-tight manner through the wall of the autoclave into the latter, a contact pressure in the form of an additional unidirectional load is exerted on the test element by means of a unit arranged inside the autoclave, and both the contact pressure and the torsional moment acting on the test element are determined and indicated outside the autoclave.