Device and method for moving display window on screen

PURPOSE: A device capable of moving a display window and a method thereof are provided to effectively move a display window overlapped with a key input window when the key input window for inputting keys on a screen is displayed. CONSTITUTION: A display unit (300) displays a part of a key input window, and a moving location determination unit (200) determines a moving direction of a first display window corresponding to the key input window according to the display of the key input window. The display unit moves the first display window based on the moving location. When the key input window is overlapped with the first display window, the display unit moves the first display window. An input unit (100) receives a user input selecting a key input field of the first display window. When the key input field is selected, the display unit displays the key input window. [Reference numerals] (100) Input unit; (200) Moving location determination unit; (300) Display unit; (400) Memory unit; (500) Control unit