To provide a communication system capable of saving space of whole of the system, reducing costs and also providing contents from a mobile telephone, that system is a system controlling a device via network and controlling by using mobile terminals.

This communication system comprises a mobile telephone 103 connected to a controller 102 and a terminal 108 connected to network 111, a Web browser 110 requests a control for a device 101, a client side communication controller 109 transmits the request to the mobile telephone 103, a Web server 105 transfers the request received at a server side communication controller 104 to an expansion module 106 so as to control the controller 102.