A marker detection method in which a magnetic detection unit (11) of a vehicle side that includes a plurality of magnetic sensors arranged in a vehicle width direction is used to detect magnetic markers (10) that are laid in a road, the method executes detection of a center position in the vehicle width direction of a magnetic distribution that acts on the magnetic detection unit (11) and processing of an index representing a degree of a positional change of the center position when a vehicle (5) passes over the magnetic markers (10) to determine a possibility of the presence of magnetic generation sources that causes disturbance, thereby suppressing erroneous detection of the magnetic markers (10).