To provide an on-vehicle radar apparatus for restraining a measurement error of a distance or the like even if the sensitivity to oscillation frequency or frequency modulated voltage of a transmission wave changes with a temperature or passage of time.

This on-vehicle radar apparatus is provided with an oscillator for comparison with a transmission frequency and a means for mixing a signal of the oscillator with the transmission signal to obtain an intermediate frequency (IF) signal, and the comparison result is used to correct the modulation sensitivity.