A radar target detection method in which an azimuth at which a target is located is detected on the basis of reception signals obtained through antenna elements of an array antenna by detecting a change in levels of spectrum peaks in an azimuth spectrum of reception signal intensities, calculating a level of correlation between the level change of each spectrum peak and a directivity pattern of the array antenna in an azimuth range corresponding to the spectrum peak, and determining an azimuth corresponding to one of the spectrum peaks having the highest corresponding correlation level to be the azimuth at which the target is located.