[en] The first observation of the nuclear resonant scattering from the 37.1-keV level of ¹²¹Sb and the 22.5-keV level of ¹⁴⁹Sm excited by synchrotron radiation is reported. Delayed emission of fluorescent K or L X-rays following the internal conversion process is mainly used to observe this resonance. The evaluated energy of each excited level was 37.147±0.023 keV for ¹²¹Sb and 22.496±0.022 keV for ¹⁴⁹Sm. Each half-life of the excited level was evaluated to be 3.47±0.39 ns for ¹²¹Sb and 7.40±1.15 ns for ¹⁴⁹Sm. These values agree well with the reported values for each level. (author)