The magnetic field intensity distribution of a magnetic material sample, such as a magnetoresistive device, is measured with a probe having a tip portion of a magnetic material to which current is made to flow from a power source to the magnetic material. The probe is scanned relative to the surface of the magnetic material sample in two modes. In a first mode, the probe is scanned by being oscillated in a vertical direction to tap a surface of the sample to be tested. In a second mode, the probe is scanned while being held in contact with the measured surface. Corresponding first and second output signals from the two modes of scanning are processed to calculate the magnetic field intensity distribution of the sample magnetic material.