An air conditioner comprising: a housing (10, 20) comprising an air discharge plate that comprises a plurality of holes and an outlet; a heat exchanger located inside the housing; a blower fan configured to blow air heat-exchanged with the heat exchanger toward the air discharge plate or the outlet; a blade configured to rotate to be located at (i) a first position to close the outlet, (ii) a second position to open the outlet to guide air discharged through the outlet from the blower fan straight ahead, or (iii) a third position to open the outlet to guide air discharged through the outlet from the blower fan downward, wherein the blade comprises: a first blade comprising a plurality of blade holes and a plate having a size corresponding to that of the outlet, and a second blade spaced apart from the first blade, characterised in that the second blade is configured to guide air blown from the blower fan toward the air discharge plate when the first blade is located at the first position and to guide air passing through the outlet and flowing towards the first blade downward to prevent air flowing towards the blade holes of the first blade when the blade is located at the third position, and wherein the blade is configured to close the outlet to discharge air out of the housings (10 and 20) through the blade holes of the first blade and the plurality of holes of the air discharge plate at the first position. a housing (10, 20) comprising an air discharge plate that comprises a plurality of holes and an outlet; a heat exchanger located inside the housing; a blower fan configured to blow air heat-exchanged with the heat exchanger toward the air discharge plate or the outlet; a blade configured to rotate to be located at (i) a first position to close the outlet, (ii) a second position to open the outlet to guide air discharged through the outlet from the blower fan straight ahead, or (iii) a third position to open the outlet to guide air discharged through the outlet from the blower fan downward, wherein the blade comprises: a first blade comprising a plurality of blade holes and a plate having a size corresponding to that of the outlet, and a second blade spaced apart from the first blade, characterised in that the second blade is configured to guide air blown from the blower fan toward the air discharge plate when the first blade is located at the first position and to guide air passing through the outlet and flowing towards the first blade downward to prevent air flowing towards the blade holes of the first blade when the blade is located at the third position, and wherein the blade is configured to close the outlet to discharge air out of the housings (10 and 20) through the blade holes of the first blade and the plurality of holes of the air discharge plate at the first position. a first blade comprising a plurality of blade holes and a plate having a size corresponding to that of the outlet, and a second blade spaced apart from the first blade, characterised in that the second blade is configured to guide air blown from the blower fan toward the air discharge plate when the first blade is located at the first position and to guide air passing through the outlet and flowing towards the first blade downward to prevent air flowing towards the blade holes of the first blade when the blade is located at the third position, and wherein the blade is configured to close the outlet to discharge air out of the housings (10 and 20) through the blade holes of the first blade and the plurality of holes of the air discharge plate at the first position.