H-terminated Si(100) with lateral p⁺-n junction has been imaged with emission electron microscopies as a model system where surface electric field is inhomogeneously distributed. It is clarified that mirror electron microscope has a higher sensitivity to the electric field parallel to the surface, compared to photoemission electron microscopy (PEEM) with either Hg-lamp (UV-PEEM) or synchrotron radiation to emit secondary electrons (SE-PEEM). On the other hand, intensity contrast between p-region and n-region arising from the difference in band bending, i.e., an electric field normal to surface, can be detected by UV-PEEM. It has been found in SE-PEEM that the intensity contrast becomes lost with higher kinetic energies. [DOI: 10.1380/ejssnt.2006.539]