Apparatus having touch screen and external display device using method therefor

PURPOSE: A device having a touch screen and a using method for connecting an external display device with the device are provided to show the screen through a wide screen by connecting to an external large display and to facilitate the access to an external large screen by using the touch screen as a mouse pad. CONSTITUTION: An external device connector(20) connects to the external display device. A detector(18) outputs a detection signal by detecting the connection with the external display device. A touch screen display driver(22) displays the data inputted through the touch pad on the touch screen(12). An external display driver(24) displays the inputted data on the external display device when the touch pad(12) acts like the mouse pad. A controller(14) stops the operation of the touch screen display driver(24) when detecting a detection signal, operates the external display driver(24), recognizes a point touching the touch pad(12), outputs a coordinate value matching with the position, and decides the position of a pointer on the screen of the external display device(24) by performing the calculation for mapping the coordinates value and the screen display coordinates of the external display device(24).