A display device comprising: a housing; a roller disposed inside the housing; a display unit rolled around the roller; a link (910a, 910b) comprising a first arm (911a, 911b) and a second arm (912a, 912b), wherein the first arm (911a, 911b) is rotatably mounted on the display unit, and the second arm (912a, 912b) is rotatably connected to the first arm (911a, 911b) and is rotatably mounted on the housing; a lead screw (840a, 840b) disposed inside the housing; a slider (860a, 860b) configured to move on the lead screw (840a, 840b) based on a rotation of the lead screw (840a, 840b); a rod (870a, 870b) comprising one side connected to the slider (860a, 860b) and another side connected to the second arm (912a, 912b); an upper bar coupled to an upper side of the display unit; a first lock magnet positioned at a lower side of the upper bar; a second lock magnet corresponding to the first lock magnet and positioned at an upper side of a bottom surface of the housing; characterized in that: the first lock magnet is a permanent magnet, the second lock magnet is an electromagnet, wherein a repulsive force generated between the first lock magnet and the second lock magnet is transmitted to the second arm (912a, 912b), the display device further comprises a lock processor configured to control a polarity of the second lock magnet, wherein the lock processor is configured to sense a current supplied to the second lock magnet, and to control the polarity of the second lock magnet based on the sensed current, and wherein, when a standing of the second arm (912a, 912b) with respect to the housing proceeds, the lock processor is configured to control so that a same polarity as the first lock magnet (931a, 931b) is generated in the second lock magnet, and then to control so that a different polarity from the first lock magnet is generated in the second lock magnet at a moment at which the current decreases while sensing the current flowing in the second lock magnet. a housing; a roller disposed inside the housing; a display unit rolled around the roller; a link (910a, 910b) comprising a first arm (911a, 911b) and a second arm (912a, 912b), wherein the first arm (911a, 911b) is rotatably mounted on the display unit, and the second arm (912a, 912b) is rotatably connected to the first arm (911a, 911b) and is rotatably mounted on the housing; a lead screw (840a, 840b) disposed inside the housing; a slider (860a, 860b) configured to move on the lead screw (840a, 840b) based on a rotation of the lead screw (840a, 840b); a rod (870a, 870b) comprising one side connected to the slider (860a, 860b) and another side connected to the second arm (912a, 912b); an upper bar coupled to an upper side of the display unit; a first lock magnet positioned at a lower side of the upper bar; a second lock magnet corresponding to the first lock magnet and positioned at an upper side of a bottom surface of the housing; the first lock magnet is a permanent magnet, the second lock magnet is an electromagnet, wherein a repulsive force generated between the first lock magnet and the second lock magnet is transmitted to the second arm (912a, 912b), the display device further comprises a lock processor configured to control a polarity of the second lock magnet, wherein the lock processor is configured to sense a current supplied to the second lock magnet, and to control the polarity of the second lock magnet based on the sensed current, and wherein, when a standing of the second arm (912a, 912b) with respect to the housing proceeds, the lock processor is configured to control so that a same polarity as the first lock magnet (931a, 931b) is generated in the second lock magnet, and then to control so that a different polarity from the first lock magnet is generated in the second lock magnet at a moment at which the current decreases while sensing the current flowing in the second lock magnet.