A folding portable radio device is provided with a first display part on the inner side of a case 16 and a second display part 29 on the outer side of the case 16, and owner's name is displayed in the second display part 29 at the idle state. In order to display owner's name in the second display part 29, in case that the folding portable radio device is in a waiting state, a user operates a key operation part to input owner's name and registers owner's name by input of a function key of a key operation part assigned to registration, whereby hereinafter owner's name can be displayed in the second display part 29 in the waiting state.