A mobile terminal device includes a display module which displays a screen; a photographing module which is configured to face substantially the same direction as the screen; a determining module which determines, based on an image photographed by the photographing module, whether a state of a user facing the screen coincides with a predetermined determination condition indicating that the user has difficulty in browsing the screen; and a display changing module which changes a current display manner of the screen to a display manner that enhances visibility of characters displayed on the screen, as compared with the current display manner, based on a determination result by the determining module that the state of the user coincides with the determination condition.