To determine whether tab paper is inserted into sheets printed by executing a print job in a correct order.

A printing apparatus includes: an insertion means for successively inserting a plurality of sheets of tab paper between sheets to be printed by executing a print job; a storage means for storing data for inspection for detecting the insertion sequence error of the tab paper to be inserted by the insertion means from the job; a reading means for reading the images of the sheets or tab paper to be conveyed on a conveyance path; and a determination means for determining whether the insertion sequence of the tab paper to be conveyed is normal by comparing the data for inspection stored in the storage means with the image data of the tab paper or sheets to be read by the reading means.