The Doppler-free saturated spectroscopy of the CO2 and SF6 molecules is investigated experimentally by using optoacoustic detection with a resonant multipass cell. The width of the absorption dip for CO2 is measured to be about 2.5 MHz, five absorption dips for SF6 are observed in the experiments, and the dip width is about 1.9MHz. In both oases the spectral resolving power is greater than 107.