An information terminal transmits small amount data such as a command to a Web server on the internet to an asymmetric router via an interactive radio network. The asymmetric router transmits the command to the Web server via the internet. The asymmetric router transmits large amount data (for example, HTML formatted browser data) from the Web server to a data superimposing broadcast apparatus. The data superimposing broadcast apparatus determines a scheduled time of broadcasting according to a data amount. The scheduled time is transmitted to the information terminal via the asymmetric router and the interactive radio network. When the scheduled time comes, the large amount data is superimposed on an empty portion of a television signal, and is broadcasted. The information terminal carries out a predetermined processing operation whereby a broadcast receiving circuit is turned on, and the television signal on which the large amount data has been superimposed is received. The received data then can be displayed in a display device and the like. Therefore, even in a portable information terminal, it is possible to provide an interactive communication system which can transmit large amount data at a high speed.