The invention relates to a roller-changing device. The roller-changing device comprises tracks, a lifting rope suspended above the tracks, a trolley moving on the tracks and a bracket arranged at the bottom of the tracks, wherein a tightly-pressing device connected with the furnace roller is arranged in the front of the trolley, a hook is arranged at the tail end of the trolley, a self-locking device matched with the hook is arranged on the tracks and comprises a weight block, a limiting screw and a guide cylinder, the weight block is arranged inside the guide cylinder, a guide groove is formed in the weight block, the limiting screw is fixedly arranged in the side wall of the guide cylinder, and the end part of the limiting screw is located inside the guide groove. According to the roller-changing device, by virtue of the tightly-pressing device, the spindle nose of the furnace roller can be rapidly fixed, the furnace roller can be stably and rapidly pulled out from or loaded into the hearth through the trolley, the moving trolley with rollers can be automatically locked by virtue of the self-locking device and thus the baking intensity of operators due to the furnace gas is decreased and the risk that the furnace wall is rubbed by the furnace roller is reduced.