A device for mounting rotors, in particular articulated shafts, in a balancing machine has a bearing frame and a frame upper part, which is mounted on the bearing frame so as to be able to oscillate via spring bars and includes a spindle for rotatable mounting of a rotor. The frame upper part is mounted on the bearing frame via groups of spring bars, the groups being arranged at a distance from the axis of rotation of the spindle and at a distance from one another, and the longitudinal axes of the spring bars forming the spring bar groups being oriented parallel to the axis of rotation of the spindle. The spring bars forming the spring bar groups have an elongated, slender shape such that their rigidity in an axial direction is at least 100 times, in particular at least 300 times, greater than their radial flexural rigidity.