The origin and principle of scanning tunneling microscopy in reviewed. A prototype STM with a three dimensional stage which is able to select sample area and to approach the sample automatically is described, and typical images obtained by the STM are shown. Surface topograph of cleaved MoS2 (0001) shows neat arrangement of sulfur atoms with 0.316 nm lattice constant. Some defects due to vacancies and a dislocation are also distinguished. It is considered that the imaging principle of STM depends on the probe tip and the atomic arrangement of samples. Also 7 × 7 reconstructed structure of Si (111) is shown.
