1. A stationary object detection method for a scanning radar that performs scanning along a radar beam projection direction wherein, of peaks generated based on a radar signal reflected from a target, peaks having substantially the same frequency are grouped together, and a decision is made as to whether or not the frequency of said grouped peaks is equal to or higher than a predetermined value, and wherein if said peak frequency is equal to or higher than said predetermined value, then a decision is made as to whether or not the number of said grouped peaks is equal to or greater than a predetermined number and, if the number of said peaks is equal to or greater than said predetermined number, it is decided that said target is an overhead bridge candidate or an overhead bridge.