A flexible display apparatus is disclosed. In one aspect, the apparatus includes a flexible display panel including a first surface, a second surface facing the first surface, and a side surface that connects the first surface and the second surface. The apparatus also includes a passivation layer that is disposed on at least one of the first surface, the second surface, and the side surface of the display panel and includes a viscoelastic fluid and a vessel unit that contains the viscoelastic fluid therein.