a lower body including a suction hole;

a first tower disposed above the lower body, and including a first slit discharging an air;

a second tower disposed above the lower body, spaced apart from the first tower in lateral direction, and including a second slit discharging air;

a blowing space formed between the first tower and the second tower, and the air discharged from the first slit and the second slit flows, and

wherein the first tower includes a first boundary surface facing the blowing space and in which the first slit is disposed,

wherein the second tower includes a second boundary surface facing the blowing space and in which the second slit is disposed,

wherein the first boundary surface and the second boundary surface are formed convexly toward each other, and a shortest distance point where a distance between the first boundary surface and the second boundary surface is shortest is formed at a central part in front-rear direction,

wherein each of the first and second slits is disposed near a rear end of the first and second boundary surfaces, and an opening direction of the first and second slits are facing each other, and

wherein the first and second slits are spaced backward from the shortest distance point.