The construction of a microminiature axial magnetic field probe, and its associated instrumentation, is described. With an active area measuring approximately 100×100 &mgr;, and an over‐all cross‐sectional dimension of 1.2 mm diam, the probe is sufficiently small to be maneuvered about within the polepiece of a conventional electron microscope objective lens. The axial component of the magnetic field can be measured on, as well as off, the axis of the polepiece to a higher spatial resolution than can be achieved with a commercial axial probe.