For stable battery performance, it is essential to control the surface condition and particle shape of NMC (lithium nickel manganese cobalt oxide), which is used as a cathode active material in lithium‑ion rechargeable batteries. However, operators must manually measure large numbers of NMC particles and observe their surfaces at high magnification with scanning electron microscopes (SEMs), which requires significant time and effort. Recent SEMs are equipped with fast and accurate automatic contrast/brightness (ACB), auto focus (AF), and auto astigmatism correction (AS). They also provide external control APIs, allowing users to develop their own automation programs. In this study, to address the issues above, we automated high‑magnification observation of NMC particles by using the SEM external control API and Python®, based on an optimized sample preparation suitable for automatic measurement.