PROBLEM TO BE SOLVED: To perform a position adjustment of a radar reflection object by a simple method irrespective of a mounting position of a radar.SOLUTION: A position adjustment method of a radar reflection object according to the present invention is the position adjustment method that is used in performing a position adjustment of a radar mounted to a vehicle. The position adjustment method includes: aligning a first end part 230-1 of a preliminarily set first length α in a first string 230 having the first length with one of two reference objects 210 and 220 of a vehicle 100 arranged in bilateral symmetry with respect to a virtual center axis 150 extending in directions ahead and behind the vehicle 100; aligning a first end part 240-1 of a preliminarily set second length &bgr; in a second string 240 having the second length &bgr; with the other one of the two reference objects 210 and 220; and determining an intersection location 250 where a second end part 230-2 of the first length α and a
