PURPOSE: To display a read image automatically in a proper direction corre sponding to document size without troubling an operator.

CONSTITUTION: Image size information stored on an optical disk 19 is stored in a main memory 38 and an image stored on the optical disk 19 is stored in a page memory 40; and display condition parameters in which display directions of display made on a CRT display device 24 by image sizes are set are previously stared on a magnetic disk 26 and a CPU 34 reads the image size information stored in the main memory 38 and the display condition parameter file stored on the magnet disk 26. A rotation processing circuit 48 processes the display direction of the image stored in the page memory 40 according to the read information and stores the result in a display memory 42 and a display control part 44 displays the image, stored in the display memory 42, on the CRT display device 24.