In a radar apparatus, IF beat signals are detected in a first section and a second section serving as two adjacent frequency up-modulation sections of a transmitted wave. Frequency conversions such as FFTs are performed on the IF beat signals so that the frequency spectra are obtained. Subsequently, peak frequencies are detected from the frequency spectra in the corresponding sections, and the phase difference between the peak frequencies is determined. Since the phase difference calculated in this manner depends on the relative moving distance Δr during the interval between the first section and the second section, the relative moving distance Δr, the relative distance, and the relative velocity at this moment can be calculated from the phase difference.