In a method for determining geometrical characteristics (d) of an anomaly (12) which changes the electrical conductivity in the region near the surface of an electrically conducting, in particular a metallic test object (10), a considerable simplification is achieved in that, in the region of the anomaly (12) in the test object (10), eddy currents (13, 14) of different frequencies are excited, and the magnetic field (By,0), which is produced by the excited eddy currents, is scanned in the vicinity of the anomaly (12) and the geometric characteristics of the anomaly are exclusively deduced from the distribution of the magnetic field (By,0).