Scanning probe microscopy (SPM) is a powerful method for visualizing the structure of materials at the nanoscale. In particular, atomic force microscopy (AFM) has become one of the most used analytical tools in various fields such as physics, chemistry, and biology. Here, we introduce representative works in nano-bioscience. First, we look back on the history of SPM and introduce the application of AFM in this field. Next, we review surface force and single-molecule force measurements, which unveiled molecular processes at biointerfaces. Surface force measurements revealed the mechanism underlying the macroscopically observed protein and cell resistance of artificial monolayers and biomolecules. Meanwhile, single-molecule force spectroscopy has enabled researchers to explore the complex interaction of biomolecules from a microscopic viewpoint. These findings will contribute not only to the fundamental understanding of biomolecular processes but also to the design of new nano-biodevices.