A cleaning system (100) comprises an air conditioner (5) and an air cleaner (3). The air conditioner (5) includes an air direction changing part (51) and a control unit (56). The air direction changing part (51) changes the air direction of air that is sent from a blower opening (P2) among three levels in the vertical direction. The control unit (56) sets the operation mode of the air conditioner (5) to a dust collection mode in response to a prescribed trigger. The dust collection mode indicates an operation mode in which indoor dust is caused to fall to the floor (FL). Among the three levels of air direction, a first-level air direction (A1) faces farther upward than a second-level air direction (A2), and the second-level air direction (A2) faces farther upward than a third-level air direction (A3). In the dust collection mode, the air direction change part (51) sends air inside in the first-level air direction (A1) during a first prescribed period, and sends air inside in the second-level air direction (A2) during a second prescribed period after the first prescribed period has elapsed.