To keep a commodity master excellent in quality on a timely manner by constituting a general common commodity master database so as to be directly downloadable and usable by a selling store that is a user can download and use the commodity master, and directly maintainable by a manufacturing agent and a distribution source.

The general common commodity master database is placed in a Web site on the Internet, so that the user preliminarily permitted to use can retrieve the master with a JAN code or commodity name and download a hit record. If no hit result is obtained, or the commodity information is not present on the general common commodity master database, the store side that is the user performs a write-in to the database. The manufacturing agent and the distribution source directly register commodity master information to the general common commodity master database, whereby they can receive the providing of sales result summary information on the store side in return for this.