An air conditioner including: a housing including a cylinder portion, an inlet, and an outlet formed in a lower portion of the cylinder portion and being in a shape of an arc; a heat exchanger positioned inside the cylinder portion and being in a shape of an arc; and a plurality of blades configured to selectively open or block the outlet, wherein the plurality of blades are arranged along a circumferential direction of the outlet and configured to move back and forth in a radial direction of the outlet to open or block the outlet, and each of the plurality of blades includes a plurality of holes configured to enable, upon blocking of the outlet by the blade, air entered the inlet to be discharged to outside of the housing through the blade.