To construct an application processing system which collects information by Internet mail from an unspecific Internet user and performs data processing without using a server by using a processor PC connected directly to the Internet.

A homepage created to collect Internet user information is preliminarily registered in a provider, and data inputted by the unspecific Internet user that uses the homepage are rewritten into Internet mail by using a CGI function provided by the provider and transmitted to the mail ID of a system provider. The data are received by the mail data analysis program of a processing performing device (PC) managed by the system provider, subjected to a syntax analysis/consistency checking and subsequently written in an input data file in the case of proper data. Meanwhile, in the case of improper data, error mail is prepared and sent back to the Internet mail of the user who has inputted the data.