An IF server sends e-mail to a mobile device MS. This e-mail includes an application specifier that specifies startup of a Java application stored in mobile device MS and a data specifier that includes data used in operations executed by mobile device MS in accordance with a Java application. On the other hand, the ADF for the Java application stored in mobile device MS includes trusted source data containing a plurality of e-mail addresses that indicate trusted origins. Mobile device MS compares the e-mail transmission origin address with the trusted source data. Mobile device MS, only in thecase where the transmission origin address of the received e-mail is included in the trusted source data, starts up a Java application based on an application specifier included in said e-mail, and uses data included in said data specifier in operations executed by that Java application.A mobile station (MS) determines whether or not data, acquired or generated according to a first application, may be used in processing executed according to a second application, based on data indicating the source of the data, data indicating the source of the first application that passes the data, or dataindicating the source of the second application to which the data is passed.