A postprocessing apparatus includes a support unit that supports a sheet that is transported, an abutment unit against which a leading end of the sheet supported by the support unit abuts, a postprocessing unit that performs a postprocessing operation on the sheet abutting against the abutment unit, a detection unit that detects an image formed at a predetermined position on the sheet and detects a position of the image when the sheet abuts against the abutment unit, and a changing unit that changes a position of the abutment unit relative to the postprocessing unit on the basis of the position of the image detected by the detection unit.