An air-conditioning apparatus, comprising: a refrigerant circuit including a compressor, a heat source side heat exchanger, an expansion device (16,16a-b), and a refrigerant side passage of a heat exchanger (15,15a-b) related to heat medium connected by piping in series, the refrigerant circuit circulating a heat source side refrigerant; and a heat medium circuit including a heat medium side passage of the heat exchanger (15,15a-b) related to heat medium, a pump (21,21a-b), a first heat medium flow switching device (22,22a-b), a use side heat exchanger (26,26a-b), a heat medium flow control device (25,25a-d), and a second heat medium flow switching device (23,23a-d) connected by piping in series, the heat medium circuit circulating a heat medium, wherein the compressor and the heat source side heat exchanger are accommodated in an outdoor unit, the use side heat exchanger (26,26a-b) is accommodated in an indoor unit (2,2a-d), characterized in that the heat exchanger (15,15a-b) related to heat medium, the expansion device (16,16a-b), and the pump (21,21a-b) are accommodated in a heat medium relay unit, the first heat medium flow switching device (22,22a-b) and the second heat medium flow switching device (23,23a-d) are accommodated in a heat medium regulating unit, the heat medium flow control device (25,25a-d) is accommodated in the heat medium regulating unit or the indoor unit (2,2a-d), the outdoor unit, the heat medium relay unit, the heat medium regulating unit, and the indoor unit (2,2a-d) have separately different casings, the outdoor unit and the heat medium relay unit are connected with at least two refrigerant pipings, the heat medium relay unit and the heat medium regulating unit are connected with four heat medium pipings, the heat medium regulating unit and the indoor unit (2,2a-d) are connected with two heat medium pipings, a first controller controlling a rotation speed of the pump (21,21a-b) and a second controller controlling a rotation speed of the compressor on the basis of a condensing temperature or a pseudo-condensation temperature when a high-pressure side is in a supercritical state and/or an evaporating temperature are provided, and the first controller and the second controller are connected by wire or wireless allowing cooperative control. a refrigerant circuit including a compressor, a heat source side heat exchanger, an expansion device (16,16a-b), and a refrigerant side passage of a heat exchanger (15,15a-b) related to heat medium connected by piping in series, the refrigerant circuit circulating a heat source side refrigerant; and a heat medium circuit including a heat medium side passage of the heat exchanger (15,15a-b) related to heat medium, a pump (21,21a-b), a first heat medium flow switching device (22,22a-b), a use side heat exchanger (26,26a-b), a heat medium flow control device (25,25a-d), and a second heat medium flow switching device (23,23a-d) connected by piping in series, the heat medium circuit circulating a heat medium, wherein the compressor and the heat source side heat exchanger are accommodated in an outdoor unit, the use side heat exchanger (26,26a-b) is accommodated in an indoor unit (2,2a-d), characterized in that the heat exchanger (15,15a-b) related to heat medium, the expansion device (16,16a-b), and the pump (21,21a-b) are accommodated in a heat medium relay unit, the first heat medium flow switching device (22,22a-b) and the second heat medium flow switching device (23,23a-d) are accommodated in a heat medium regulating unit, the heat medium flow control device (25,25a-d) is accommodated in the heat medium regulating unit or the indoor unit (2,2a-d), the outdoor unit, the heat medium relay unit, the heat medium regulating unit, and the indoor unit (2,2a-d) have separately different casings, the outdoor unit and the heat medium relay unit are connected with at least two refrigerant pipings, the heat medium relay unit and the heat medium regulating unit are connected with four heat medium pipings, the heat medium regulating unit and the indoor unit (2,2a-d) are connected with two heat medium pipings, a first controller controlling a rotation speed of the pump (21,21a-b) and a second controller controlling a rotation speed of the compressor on the basis of a condensing temperature or a pseudo-condensation temperature when a high-pressure side is in a supercritical state and/or an evaporating temperature are provided, and the first controller and the second controller are connected by wire or wireless allowing cooperative control.