While the development of new generation magnetic storage medium requires an instrument to characterize magnetic nanostructures finer than 20 nm, none of standard apparatus with such performance was available. New magnetic force microscope (MFM) and the MFM probe have been successfully developed. The probe was fabricated by use of carbon nanotube and technology for vapor depositing magnetic materials, leading to characterization of magnetic storage medium with 10 nm resolution. The newly developed MFM is expected to become a powerful research tool in areas of magnetic storage and spin electronics. This work was performed in AIST in collaboration with SII Nanotechnology and Fujitsu Ltd. under Nanotechnology program, NEDO.