Dynamically measuring the unbalance of a rotor arranged in a device housing (1) and rotating at high angular velocity, wherein the rotor is supported in a separate bearing housing (14), involves the following steps: fastening the bearing housing (14) on the device housing (1) with interposition of resiliently yielding elements (6) so that the bearing housing (14) can be moved relative to the device housing (1) in at least two spatial dimensions and the rotor is arranged in a working position in the device housing (1) suitable for driving, accelerating the rotor, measuring the vibrations induced by unbalance while the rotor rotates at a substantially normal working speed, determining the phase position of the induced vibrations to the relative position of the rotor at the measuring speeds, and using the measured vibrations and the phase position to determine the unbalance of the rotor to be compensated.