Sorting apparatus, mail processing system, and sorting method

In dispatch sorting, a sorting system requires an operator to input sorting information through an information input unit for mails whose sorting information could not be identified and sorts the mails into delivery stations based on the information input as the sorting information through the information input unit, as well as stores the information input through the information input unit in an input information database. Further, the sorting system sorts the input information stored in the input information database into delivery stations, as well as stores the summary data representing per-digit or per-hierarchy number of the input information in a summary data table.