A terminal device, an information display system and a method of controlling the terminal device are disclosed. The terminal device includes a camera unit configured to capture a picture in which an external device connected with a network is included, a control unit configured to detect the external device from the captured picture, a communication unit configured to transmit and receive data and a display unit configured to display the captured picture. If the detected external device in the captured picture is selected, the control unit controls the communication unit to receive information on the external device based on a sensing history of the external device and can control the display unit to display the received information on the external device on the display unit.