A method and device capable of automating registration of a transmission mail address allowed for reception in a white list and reducing a user burden without an input error is provided. From a mobile unit, in respect of registration of a transmission address allowed for reception in a white list of an e-mail server, it becomes possible to eliminate a work of making an operation of inputting list data for updating the white list by utilizing information electronically stored in an address directory, and further, it becomes possible to reliably register the latest data free of an input error as a white list. In addition, the data stored in the white list of the e-mail server is transferred to a mobile terminal device, thereby making it easy to update an address directory due to a device model change.