First and second towers may discharge air. An airflow guide or converter may change a direction of the air discharged from the first tower and the second tower by moving a gate inside and outside of at least one of the first or second towers so as to block discharged air flowing forward and selectively facilitate an upward air flow. The airflow converter may include a guide motor to provide a driving force, the gate, which may reciprocate between the inside and the outside of the first and/or second towers; and a board guider connected to the gate to transmit a driving force of the guide motor to the gate as a linear motion force.