[en] Series of works on research of conversion line shift effect in ¹⁸¹Ta was continued. The effect is caused by the electron interaction with the magnetic moment of the nucleus (hyperfine interaction) under the condition of nonstatistical population of the components determined by the spin selection rules. The method that enables to measure small (about 1 eV) conversion line shifts was developed. The experimental value of hyperfine shift for K476 - K482 doublet in ¹⁸¹Ta was determined for the first time. It is equal to 4,9/2,0 eV and agrees with theoretical value of 2,6 eV