A virtual computer server apparatus includes an image information memory to store image information upon dividing into pages, the page being a memory of a predetermined size, an update unit configured to update the image information stored in the image information memory in accordance with operation of the application program, an update page detection unit configured to detect an update page from the pages storing image information transmitted to the terminal and displayed by the terminal as a display area, an update image detection unit configured to detect the image information updated by the update unit from image information in the update page before updated and image information in the update page after updated.