Magnetic marker detection method and detection system

A magnetic marker detection method for a vehicle including a sensor array with a plurality of magnetic sensors that obtain magnetic measurement values arrayed in a width direction to detect a magnetic marker laid in a traveling road, the magnetic marker detection method comprising:

• a differential process of obtaining, based on a distribution of the magnetic measurement values of the plurality of magnetic sensors configuring the sensor array, for each combination of two positions spaced with a predetermined space, a difference between values configuring the distribution or values configuring a line representing the distribution;
• an arithmetic process for detecting the magnetic marker or for detecting a position of the magnetic marker by taking the difference for the each combination obtained by the differential process as an input value;
• and
• a setting process of selectively setting the predetermined space for obtaining the difference, wherein
• the setting process can be performed during traveling of the vehicle, and the predetermined space can be changed by the setting process during the traveling of the vehicle.