A mobile phone (1) includes: a blank area detection section (55) which detects a blank area whose size is determined by subtracting, from an entire area of a display screen, an image display area where an image is displayed and a character string display area where a character string is displayed; and a reposition control section (51) which changes the position or size of at least one of the image and the character string from an initial state, in such a way as to allow the image and the character string to be displayed in a single display screen. On this account, an image and a character string associated therewith are efficiently displayable in a single screen.