A flexible display device is disclosed. The flexible display device includes a first body, a second body, a flexible display, and a lubrication rail. The lubrication rail is made of self-lubricating engineering plastic, and is provided as a pair of lubrication rails. When the first body and the second body move relative to each other, a surface of the lubrication rail significantly reduces friction that occurs in a contact portion between the first body and the second body.