A post-processing device includes a first discharge unit, a processing tray, an end alignment portion, a transport unit that comes into contact with an upperface of a medium placed on the processing tray and transports the medium to the end alignment portion, a position changing unit that changes the relative position of the transport unit with respect to the processing tray, a controller, and a post-processing unit that performs a post-process on the medium on the processing tray, wherein the position changing unit is configured to move the transport unit to a transport position to which the medium is transported and a standby position farther away from the processing tray than the transport position, wherein the controller changes the standby position based on the processing information related to the process performed on the medium, and wherein the processing information includes information about a process performed on the first medium.