A remaining water suction device may include: a suction nozzle, a water separation chamber configured to be connected to a discharge port of the suction nozzle and provided with a water discharge port and an air discharge port, and a buffer tank configured to be connected to the water discharge port and store water separated from the water separation chamber. The remaining water suction device may include a water transfer pump configured to transfer the water stored in the buffer tank, a water storage tank configured to store the water transferred through the water transfer pump, a suction fan configured to provide a suction force to the air discharge port, and a suction motor configured to drive the suction fan.