A flexible display apparatus comprises: a display panel having first and second bending areas bendable at first and second angles along a bending line, first and second display areas extending from the first and second bending areas; a first sensor unit which generates a first sensing signal by measuring the degree of deformation of at least one of the first and second bending areas; a second sensor unit which generates a second sensing signal by measuring the first angle; a third sensor unit which generates a third sensing signal by measuring the second angle; and a controller which receives the first through third sensing signals, determines one of the first and second display areas to be a main viewing area based on the first through third sensing signals, and adjusts a display state of the main viewing area.