An air conditioner includes a cabinet positioned on an indoor ceiling. The air conditioner also includes a front panel that is coupled to the cabinet and has an air inlet. The air conditioner further includes a suction panel coupled to the front panel and configured to move to open or close the inlet. In addition, the air conditioner includes a sensor unit positioned on the suction panel, configured to detect a position of an indoor person, and configured to move downward with respect to the suction panel in response to an operation instruction.