A display device includes: a housing; a roller rotatably disposed on the housing; a flexible display that is rolled around the roller or unrolled from the roller; a first arm connected to the flexible display; an arm supporter provided in the housing; an arm shaft rotatably supported to the arm supporter; a second arm coupled to the arm shaft and rotated together with the arm shaft to rotate the first arm; a rotation mechanism connected to the second arm to rotate the second arm about the arm shaft; and an angle sensor module connected to at least one of the arm shaft and the second arm.