To satisfactorily solve the problem such as access authentications or the like of whole employees to a centralized database.

In a step (1), a stuff inputs an employee number and a password to each PC. Thus, in a step (2), an employee master provided to an in-house server is referred to, the authentication of an access privilege to a database is performed and a company code to which the company employee applicable to the employee number belongs is acquired. Then, in a step (3), access to the database is performed using the acquired company code as a key and the control of a display screen, etc. of article purchase application, etc. is performed according to parameters, etc. of each company. Furthermore, in a step (4), for example, information inputted by the article purchase application is held, and in a step (5), the stored information is provided to a PC which serves as a terminal of an accounting system and used for required processing. In addition, also in this case, the stored information is processed as if it is direct information from each company in the accounting system and an order receiving/placing system by the addition of the company code.