A post-processing device includes an introductory feed path, a processing tray, a post-processing section, a catch tray, a sheet delivery section, and a control section. The post-processing section is configured to perform post-processing on the sheet placed on the processing tray. The catch tray is disposed below the processing tray. The sheet delivery section has an upper rotary member and a lower rotary member which are disposed at an end of the processing tray lying on a catch tray side so as to be movable toward and away from each other. The control section causes the upper rotary member and the lower rotary member to press against each other at latest by the time a leading edge of a first sheet of a group of sheets to be post-processed at a time is brought into contact with the catch tray.