A method for controlling a curvature of a display device as a control method of the curvature of the display device including a flexible display panel, a curvature change member, a controller, and a photo sensor includes: measuring an amount of a light incident to the flexible display panel by using a photo sensor; confirming a position of a part where the amount of the measured light is more than a predetermined reference value in the flexible display panel when the amount of the measured light is more than the reference value; and changing the curvature around the part where the amount of the measured light is more than the reference value in the flexible display panel by using the curvature change member.