Provided is a post-processing apparatus which sequentially receives sheets one by one from an image forming apparatus to execute a post-processing on the sheets, including: a first transport device which receives the sheets delivered from the image forming apparatus and transports the sheets; a sheet overlap device which stays the sheets transported by the first transport device and causes another sheet transported sequentially by the first transport device to overlap at least one stayed sheet; a second transport device which transports a plurality of sheets overlapping each other by the sheet overlap device; a plurality of stacking devices capable of stacking a plurality of sheets transported by the second transport device; and a controller which changes control of sheet overlapping caused by the sheet overlap device depending on which stacking device selected from among the plurality of stacking devices the sheets are to be transported to.