PURPOSE: To provide an address information management system capable of simply retrieving a new zip code consisting of 8 digits, e.g. from address information or simply obtaining necessary address information from a zip code.

CONSTITUTION: A place name data base 3a for retrieving address information concerned and its zip code based upon place name information such as prefecture name data is prepared in an FDD 3. A CPU 1 retrieves the data base 3a based upon the place name information such as inputted prefecture name data and outputs a new zip code consisting of 8 digits corresponding to the address information concerned. On the other hand, the CPU 1 retrieves the data base 3a based upon a conventional zip code to be a part of the inputted new zip code and outputs address information corresponding to the new zip code.