A write-head positioning method includes steps of positioning a write head on a first track of a storage medium on the basis of a servo signal and writing a signal on the first track, positioning the write head on second and third tracks located adjacent to opposite sides of the first track on the basis of servo signals and writing signals on the second track and the third track, positioning the read head at positions on the first track that are set at a predetermined interval in a track-width direction, and reading a signal from the first track at each position thereof, determining a signal profile that indicates a fluctuation of output values of the signals read at the respective positions on the first track, and detecting a peak position indicating a maximum output value in the determined signal profile.