We report here the measurements of vibrationally resolved resonant x-ray emission spectra of core-excited N2 and O2 molecules in the 1s → π* resonance region. The measured spectra were compared with the simulated spectra calculated based on the lifetime-vibrational interference theory. We find that the specific excitation to the v' = 0 vibrational level in the intermediate core-hole state of N2 molecule leads to clear vibrational structure (V" = 0 − 3) in both of the final electronic X 1Σ+g (participator band) and a 1Πg (spectator band) states. In contrast to that, the excitation to higher-v' vibrational levels gives rise to the complicated structure in the resultant soft x-ray emission spectra. In the case of O2 molecule, we have observed some structures arising from the vibrational progression, but we find that much higher resolution for the spectrometer is needed to observe distinct vibrational levels.