In a very conservative approach, supposing that all heat flow of the Earth is exclusively due to resonant capture of axions, emitted by ⁵⁷Fe nuclei on the Sun, inside the Earth, we obtained the limit on the mass of hadronic axion: m_α < 1.8 keV. Taking into account the release of heat from decays of ⁴⁰K, ²³²Th, ²³⁸U inside the Earth, this estimation could be improved to the value: m_α < 1.6 keV. Both of the values are less restrictive than the limits set in the devoted experiments to search for ⁵⁷Fe axions (m_α < 216...745 eV), but are much better than the limits obtained in the experiments with ⁸³Kr (m_α < 5.5 keV) and ⁷Li (m_α < 13.9...32 keV).