A device for measuring forces generated by an unbalance of a rotor, said device comprising a stationary frame, a first bearing, measuring shaft mounted rotatably about its shaft axis in the first bearing, a mounting means provided on the measuring shaft designed for attachment of the rotor, wherein the rotor is designed to be balanced in at least one compensating plane, a second bearing pivotally supporting the first bearing about a pivot axis which intersects the shaft axis and being supported on the stationary frame, a first force sensor for measuring forces generated by the unbalance of the rotating rotor and acting about the pivot axis, and a second force sensor for measuring forces generated by the unbalance of the rotating rotor and acting on the measuring shaft and on the second bearing in a direction intersecting the shaft axis.