[Problem] With a simple configuration, bookbinding can be performed such that a document sheet can be identified for each chapter by an index sheet, and a predetermined sheet can be easily turned over and opened.

[Solution] A post-processing apparatus adapted to cause a document sheet S1 having a document formed thereon and an index sheet S2 having a chapter title formed thereon to overlap each other, and to perform bookbinding such that the document sheet S1 is identifiable for each chapter by the index sheet S2, the post-processing apparatus including: an image formation unit configured to form, based on a title setting function provided in document generation software, the chapter title on the index sheet S2 according to chapter title information attached to the document; a processing formation unit 30 configured to form a cut-out or cuttable portion-to-be-processed K on the document sheet S1; and a bookbinding unit 40 configured to cause the document sheet S1 having the portion-to-be-processed K formed thereon and the index sheet S2 having the chapter title formed thereon to overlap each other such that the document sheet S1 is positioned on the index sheet S2, and to perform the bookbinding by causing the portion-to-be-processed K of the document sheet S1 and the chapter title of the index sheet S2 to coincide with each other.