Methods and apparatus provide for tilting of a joystick. When there is room for scrolling in the tilting direction, a screen is scrolled in the same direction as the tilting direction. When there is no room for scrolling, and a previous or subsequent region continuous with a present display region in the contents of a book is present within double-spread pages at the time point in question, display is switched to the previous or subsequent region. When the previous or subsequent region continuous with the present display region is not present within the double-spread pages, and the tilting direction is parallel with the opening of the pages, a page turning animation is inserted, and the display region is switched. When the tilting direction is not parallel with the opening of the pages, display is directly switched.