An air-conditioning apparatus comprising a heat exchanger and an outdoor fan supplying air to the heat exchanger , the heat exchanger , comprising: at least one heat exchanging unit including a plurality of stages of refrigerant flow passages each allowing refrigerant to flow in from an end portion on one side of each of the refrigerant flow passages, turn back at a first turn-back portion , and flow out of an end portion on an other side juxtaposed to the end portion on the one side ; and a distributing and joining unit connected to the at least one heat exchanging unit , the distributing and joining unit including a distributing flow passage allowing the refrigerant to be distributed and flow into a plurality of the end portions on the one side , and a joining flow passage allowing the refrigerant to be joined and flow out of a plurality of the end portions on the other side , the distributing and joining unit separately including a first header including the distributing flow passage formed therein and excluding the joining flow passage , and a second header juxtaposed to the first header, the second header including the joining flow passage formed therein and excluding the distributing flow passage , the first header and the second header being juxtaposed to an one end of the at least one heat exchanging unit , characterized in that the second header is a stacking type header including a plurality of plate-like members (53, 54_1 to 54_3, 55, 56_1 to 56_4) including partial flow passages (53a, 54a_1 to 54a_3, 55a, 56a) formed therein and stacked to each other so that the partial flow passages (53a, 54a_1 to 54a_3, 55a, 56a) are communicated with each other to form the distributing flow passage or the joining flow passage , and the second header is arranged on a windward side of the air supplied by the outdoor fan with resect to the first header. at least one heat exchanging unit including a plurality of stages of refrigerant flow passages each allowing refrigerant to flow in from an end portion on one side of each of the refrigerant flow passages, turn back at a first turn-back portion , and flow out of an end portion on an other side juxtaposed to the end portion on the one side ; and a distributing and joining unit connected to the at least one heat exchanging unit , the distributing and joining unit including a distributing flow passage allowing the refrigerant to be distributed and flow into a plurality of the end portions on the one side , and a joining flow passage allowing the refrigerant to be joined and flow out of a plurality of the end portions on the other side , the distributing and joining unit separately including a first header including the distributing flow passage formed therein and excluding the joining flow passage , and a second header juxtaposed to the first header, the second header including the joining flow passage formed therein and excluding the distributing flow passage , the first header and the second header being juxtaposed to an one end of the at least one heat exchanging unit , characterized in that the second header is a stacking type header including a plurality of plate-like members (53, 54_1 to 54_3, 55, 56_1 to 56_4) including partial flow passages (53a, 54a_1 to 54a_3, 55a, 56a) formed therein and stacked to each other so that the partial flow passages (53a, 54a_1 to 54a_3, 55a, 56a) are communicated with each other to form the distributing flow passage or the joining flow passage , and the second header is arranged on a windward side of the air supplied by the outdoor fan with resect to the first header. <EOS>