This paper describes micromachining of metal surfaces in air by a scanning probe microscope (SPM) which has a very sharp diamond tip mounted on the end of the cantilever beam. The sample surface of Ni is prepared by mechanical polishing from commercially available pure metal bulks. The sample surface is scanning scratched by a diamond tip with a scan width of 0.5–3 μm and a loading force of 0.5–10 μN, and topographies of the scratched area are observed by the same SPM with a loading force of less than 0.1 μN. Flat square hollows of nanometer‐scale depth are obtained. The scratched depth is increased with increasing loading force and repetition numbers of scratching. The scratched depth is also strongly dependent on numbers of x direction scan line, but scarcely on x direction scan rate and x–y direction scan width. Results obtained indicate that the nanoscale thickness material removal can be controlled.