A method for controlling a foldable display device comprises displaying first content provided from a first application on a first display region and second content provided from a second application on a second display region in a folded state of the foldable display device, the first application and the second application being applications which are previously installed in the foldable display device; generating a third display region by merging the first display region and the second display region with each other and generating a third application by using at least one of the first application and the second application if the foldable display device is unfolded; and displaying third content provided from the third application on the third display region, the third content being the content generated by reorganizing the first content and the second content.