This paper describes micromachining of pure metal surfaces in air by a scanning probe microscope that has a very sharp diamond tip mounted on the end of a cantilever beam. Samples of pure metals, such as Ni, Cu, and Au, were prepared by vapor deposition or mechanical polishing of bulk metals. Sample surfaces were scratched with x-y scanning of 3 mum x direction span, 30 nm y direction feed and 0.98-19.6 muN loading force, and topographies of the scratched area were observed. On the scanning-scratched surfaces of Cu and Au, the ridge caused by the adhesion of removed materials were observed. On the other hand, in the case of Ni, flat square hollows of 5-50 nm depth were obtained. The mechanism of micromachining ’should be determined by several factors such as plasticity, adhesive property, and oxide surface of metals. The method presented here will be powerful for micromachining of various materials.