An air conditioner comprising: a housing comprising a blowing port ; and an airflow guide unit installed in the blowing port configured to be rotatable about a rotation shaft so to provide a state of covering the blowing port and a state of opening the blowing port to guide the airflow to be discharged, the airflow guide unit comprising a main blade and sub-blades ; characterised in that : the main blade is configured to cover or open the blowing port ; and the sub-blades is a pair of sub-blades integrally configured through coupling with the main blade wherein in a state in which the main blade opens the blowing port , the pair of sub-blades is spaced downwardly apart from the main blade , disposed in a flow passage of the blowing port such that outer surfaces thereof are in contact with airflow in the blowing port as a whole, and having different inclination angles, the pair of sub-blades comprises a first sub-blade disposed in the blowing port and a second sub-blade disposed in the rear of the first sub-blade , and wherein the first sub-blade and the second sub-blade are spaced apart from each other in the horizontal direction and fixed to each other on each of the opposite side surfaces . a housing comprising a blowing port ; and an airflow guide unit installed in the blowing port configured to be rotatable about a rotation shaft so to provide a state of covering the blowing port and a state of opening the blowing port to guide the airflow to be discharged, the airflow guide unit comprising a main blade and sub-blades ; characterised in that : the main blade is configured to cover or open the blowing port ; and the sub-blades is a pair of sub-blades integrally configured through coupling with the main blade wherein in a state in which the main blade opens the blowing port , the pair of sub-blades is spaced downwardly apart from the main blade , disposed in a flow passage of the blowing port such that outer surfaces thereof are in contact with airflow in the blowing port as a whole, and having different inclination angles, the pair of sub-blades comprises a first sub-blade disposed in the blowing port and a second sub-blade disposed in the rear of the first sub-blade , and wherein the first sub-blade and the second sub-blade are spaced apart from each other in the horizontal direction and fixed to each other on each of the opposite side surfaces . the main blade is configured to cover or open the blowing port ; and the sub-blades is a pair of sub-blades integrally configured through coupling with the main blade wherein in a state in which the main blade opens the blowing port , the pair of sub-blades is spaced downwardly apart from the main blade , disposed in a flow passage of the blowing port such that outer surfaces thereof are in contact with airflow in the blowing port as a whole, and having different inclination angles, the pair of sub-blades comprises a first sub-blade disposed in the blowing port and a second sub-blade disposed in the rear of the first sub-blade , and wherein the first sub-blade and the second sub-blade are spaced apart from each other in the horizontal direction and fixed to each other on each of the opposite side surfaces . <EOS>