Small-scale batch fabrication of Co-included carbon nanofibers (Co-CNFs) onto commercially available Si cantilevers for scanning probe microscope by an Ar+-ion-irradiation method with a simultaneous Co supply was demonstrated (eight chips/batch). As confirmed by scanning and transmission electron microscopes equipped with energy dispersive x-ray spectroscopy, Co-CNFs were fibrous and contained Co and C. With increasing the Co supply rate, Co-CNFs decreased in length from similar to 600 to similar to 400 nm, whereas their diameter was almost independent of the Co supply rate, 20-30 nm. As proven by magnetic force microscope (MFM) measurements using the Co-CNF probes, they were applicable as MFM probes. Since various metals including alloys can be incorporated into CNFs, this ion-irradiation method with a simultaneous metal supply was believed to be quite promising for the functionalization of CNF probes for a variety of applications. (C) 2009 American Vacuum Society. [DOI: 10.1116/1.3010730]