a flexible display panel;

a panel roller which is elongated, and around which the flexible display panel is rollable;

a side frame coupled to a lateral side of the flexible display panel and rollable around the panel roller along with the flexible display panel;

a housing that provides a receiving space in which the panel roller is rotatably mounted;

a guide roller elongated along the panel roller and disposed between the panel roller and the flexible display panel when the flexible display panel is unrolled from the panel roller; and

a frame which is opposite to the guide roller with respect to the flexible display panel, and in which the guide roller is rotatably mounted,

wherein the side frame comprises:

a core elongated along the lateral side of the flexible display panel and facing the lateral side of the flexible display panel,

wherein the core is a shape memory alloy with a straight initial shape,

wherein the core is bent when the flexible display panel is rolled around the panel roller, and the flexible display panel is unbent together with the core by a restoring force of the core when the flexible display panel is unrolled from the panel roller,

wherein the housing has a slit spaced apart from a rotating shaft of the panel roller and forming an arc with respect to the rotating shaft of the panel roller, and

wherein the frame comprises at least one pin inserted into the slit so as to be movable along the arc formed by the slit.