A folder type terminal including a three-piece display unit, the folder type terminal comprising: a first display unit and a second display unit provided on the same plane in a complete open state of 180 degrees of the folder type terminal; a third display unit disposed on a rear surface of the first display unit; an input unit; and a control unit configured to: receive, via the input unit, a user selection of a composite display operation mode used for controlling power supplied to at least one of the display units of the three-piece display unit and used for instructing data to be output, which is generated according to activation of an application program, to the at least one of the display units of the three-piece display unit; control power supply to the display units of the three-piece display unit according to the composite display operation mode; and control output of the data generated by the activated application program to the display units of the three-piece display unit according to the composite display operation mode; wherein the second display unit comprises a touch panel and the third display unit comprises another touch panel; wherein, in case a specific composite display operation mode is selected, the control unit is configured to: supply power to the first display unit, the second display unit and the third display unit of the three-piece display unit; output an execution screen of the activated application program to the first display unit, and a key map for receiving, via the touch panel, a user input to the second display unit; divide a screen of the third display unit to simultaneously output the execution screen of the activated application program and the key map; and output, on the divided screen of the third display unit, the execution screen of the activated application program and the key map. a first display unit and a second display unit provided on the same plane in a complete open state of 180 degrees of the folder type terminal; a third display unit disposed on a rear surface of the first display unit; an input unit; and a control unit configured to: receive, via the input unit, a user selection of a composite display operation mode used for controlling power supplied to at least one of the display units of the three-piece display unit and used for instructing data to be output, which is generated according to activation of an application program, to the at least one of the display units of the three-piece display unit; control power supply to the display units of the three-piece display unit according to the composite display operation mode; and control output of the data generated by the activated application program to the display units of the three-piece display unit according to the composite display operation mode; wherein the second display unit comprises a touch panel and the third display unit comprises another touch panel; wherein, in case a specific composite display operation mode is selected, the control unit is configured to: supply power to the first display unit, the second display unit and the third display unit of the three-piece display unit; output an execution screen of the activated application program to the first display unit, and a key map for receiving, via the touch panel, a user input to the second display unit; divide a screen of the third display unit to simultaneously output the execution screen of the activated application program and the key map; and output, on the divided screen of the third display unit, the execution screen of the activated application program and the key map. receive, via the input unit, a user selection of a composite display operation mode used for controlling power supplied to at least one of the display units of the three-piece display unit and used for instructing data to be output, which is generated according to activation of an application program, to the at least one of the display units of the three-piece display unit; control power supply to the display units of the three-piece display unit according to the composite display operation mode; and control output of the data generated by the activated application program to the display units of the three-piece display unit according to the composite display operation mode; wherein the second display unit comprises a touch panel and the third display unit comprises another touch panel; wherein, in case a specific composite display operation mode is selected, the control unit is configured to: supply power to the first display unit, the second display unit and the third display unit of the three-piece display unit; output an execution screen of the activated application program to the first display unit, and a key map for receiving, via the touch panel, a user input to the second display unit; divide a screen of the third display unit to simultaneously output the execution screen of the activated application program and the key map; and output, on the divided screen of the third display unit, the execution screen of the activated application program and the key map. supply power to the first display unit, the second display unit and the third display unit of the three-piece display unit; output an execution screen of the activated application program to the first display unit, and a key map for receiving, via the touch panel, a user input to the second display unit; divide a screen of the third display unit to simultaneously output the execution screen of the activated application program and the key map; and output, on the divided screen of the third display unit, the execution screen of the activated application program and the key map.