To provide a mobile terminal apparatus for displaying an image by selecting the optimum display screen without adding a special process to a program operating on the mobile terminal apparatus, a mobile terminal apparatus 100 includes a program execution unit 102 for executing a desired program and output display information, a direction detection unit 103 for detecting the direction of a display screen 106, a display information conversion unit 104 for converting display information on the basis of the direction of the display screen 106, the size of the display information, etc., and a display processing unit 105 for displaying the display information on the display screen 106.