We report a reliable nanofabrication on An cluster films using an atomic force microscope (AFM) without the occurrence of tip damage or serious mass transfer between tip and sample. Noncontact mode of AFM equipped with W2C coated tip is used, and the field emission current amounting to similar to500 pA is observed, indicating the noncontact nature of our nanofabrication method. We reproducibly create dots and lines having widths as small as 50 nm. The mechanism is explained by effective local heating due to the low thermal conductivity of granular Au films and by concurrent field induced diffusion of Au clusters. (C) 2003 American Vacuum Society.