A virtual image eliminating apparatus and its method at the time when the position of a radio wave transmitting source is measured, in which the virtual image is eliminated automatically with high reliability, are provided. The virtual image eliminating apparatus provides plural bearing measuring instruments and a controlling and displaying instrument. The controlling and displaying instrument receives the measured results from the plural bearing measuring instruments. The controlling and displaying instrument calculates estimated radio wave transmitting intensity in all of the combinations of bearing lines, which formed an intersection point. And the controlling and displaying instrument judges whether each of the intersection points is a real image or a virtual image based on the difference between the estimated radio wave transmitting intensity in one combination of the bearing lines formed the intersection point. And the controlling and displaying instrument displays the bearing lines and the real image and the virtual image.