Transmission antennas (2-#1 to 2-#M) transmit radiowaves of frequency bands uncorrelated with each other. Receivers (5-#1 to 5-#L) receives target-reflected waves reflected by a target. Pulse compressors (7-#1 to 7-#L) and transmission DBF units (8-#1 to 8-#L) suppress false peaks generated by the Doppler frequency in the target-reflected waves and combines the target-reflected waves. A reception DBF unit (9) and a target detector (10) detect the target based on the results of the combined signals.