The method of atomic emission spectrometry with arc spectrum excitation provides determination of rare earth elements (REE) in geological samples by direct analysis of solid samples without a long-term preliminary sample preparation. Using the analysis of a rare-earth ore sample from the Tomtor niobium-rare-earth deposit as an example, we compared the analytical capabilities of a Grand Potok installation and a two-jet arc plasmatron (TJP) in combination with a DFS-458S spectrograph equipped with a multichannel emission spectrum analyzer (MAES). It is shown that a higher temperature of the TJP plasma (~7500 K) compared to that of the arc discharge (~5500 K) and the shift in the recording range of a DFS-458S spectrum to longer wavelengths (280 – 245 nm) provided a more reliable determination of REE using a larger number of analytical lines with lower detection limits. The correctness of the results of REE determination was confirmed by comparison with the data obtained by the ICP-MS method.