A frequency domain transforming unit (231-1) performs a transform into a frequency domain in such a way that a Doppler velocity bin is the same for each of different transmission frequencies. A correlation unit (232-1) generates signals based on a velocity and a range after correlation, the signals being separate for each of the transmission frequencies. An integrating unit (233-1) generates band-synthesized signals based on a velocity and a range after correlation. A target candidate detecting unit (241) performs detection of a target candidate on output signals of the integrating unit (233-1) on the basis of signal strength. A target's relative-velocity/relative-range/arrival-angle calculating unit (242) calculates a relative velocity, a relative range, and an arrival angle of the target candidate.