A folding machine for paper handkerchiefs is disclosed. The folding machine includes a longitudinal folding unit and a transverse folding unit, wherein the longitudinal folding unit executes a longitudinal folding procedure to a paper web to obtain a paper web with longitudinal folds, and the transverse folding unit receives the paper web with longitudinal folds from the longitudinal folding unit and cuts it into paper handkerchiefs before executing a transverse folding procedure to the paper handkerchiefs, thereby completing the folding process for paper handkerchiefs. After being folded longitudinally and transversely, the paper handkerchief is effectively reduced in size for packaging and is convenient for users to carry.

There is provided a sheet post-processing apparatus capable of performing eco-stapling processing to prevent a decrease in binding force by the thickness of a sheet with a simple arrangement by changing a stapling count depending on the grammage and size of a sheet and the number of sheets in consideration of the change in binding force caused by the sheet size.