The present invention is to enable folding processing to be applied to also large sheet sizes without upsizing the entire apparatus, in the sheet post-processing apparatus for performing the folding processing and binding processing on sheets, a sheet post-processing apparatus is provided with a binding processing section for performing binding processing using a binding needle on a sheet bunch inside a storage section, first folding roller pair for nipping a sheet P inside the storage section in a first position to form a first fold portion, a receiving section for receiving the sheet with the first fold portion formed fed out of the first folding roller pair, and second folding roller pair for nipping the sheet inside the receiving section in a second position to form a second fold portion.