An air conditioner comprising: a housing forming an air inlet and an air outlet disposed below the air inlet; a heat exchanger for exchanging heat with a outside air introduced into the housing through the air inlet; a blowing fan disposed inside the housing and in an upper rear side of the air outlet, and rotatable about a rotational axis formed in a left-right direction so that air suctioned through the air inlet flows toward the air outlet; a lower guide guiding air, discharged to a rear side and a lower side of the blowing fan, toward the air outlet; and an upper guide disposed above the lower guide to form a discharge flow path with the lower guide in such a way that a cross section of the discharge flow path from the blowing fan to the air outlet is extended gradually toward the air outlet, wherein the upper guide forms a curved surface at an end adjacent to the air outlet, the surface which is convex in a direction toward the air outlet, characterized in that: the upper guide comprises a plurality of protrusions formed at an upstream side of the upper guide to vertically protrude from a surface formed by the upper guide, and spaced apart from each other in a rotational axis direction of the blowing fan, and the upper guide is formed with a plurality of grooves elongated in a direction in which air flows along the discharge flow path, and recessed inwardly of the upper guide. a housing forming an air inlet and an air outlet disposed below the air inlet; a heat exchanger for exchanging heat with a outside air introduced into the housing through the air inlet; a blowing fan disposed inside the housing and in an upper rear side of the air outlet, and rotatable about a rotational axis formed in a left-right direction so that air suctioned through the air inlet flows toward the air outlet; a lower guide guiding air, discharged to a rear side and a lower side of the blowing fan, toward the air outlet; and an upper guide disposed above the lower guide to form a discharge flow path with the lower guide in such a way that a cross section of the discharge flow path from the blowing fan to the air outlet is extended gradually toward the air outlet, wherein the upper guide forms a curved surface at an end adjacent to the air outlet, the surface which is convex in a direction toward the air outlet, characterized in that: the upper guide comprises a plurality of protrusions formed at an upstream side of the upper guide to vertically protrude from a surface formed by the upper guide, and spaced apart from each other in a rotational axis direction of the blowing fan, and the upper guide is formed with a plurality of grooves elongated in a direction in which air flows along the discharge flow path, and recessed inwardly of the upper guide. the upper guide comprises a plurality of protrusions formed at an upstream side of the upper guide to vertically protrude from a surface formed by the upper guide, and spaced apart from each other in a rotational axis direction of the blowing fan, and the upper guide is formed with a plurality of grooves elongated in a direction in which air flows along the discharge flow path, and recessed inwardly of the upper guide.