An air-conditioning apparatus, comprising: indoor units including a plurality of use side heat exchangers that are configured to exchange heat between air with which heat is to be exchanged and a heat medium; and a heat medium relay unit including a plurality of heating/cooling units (15a, 15b) that are configured to heat or cool the heat medium, a plurality of pumps that are connected to the plurality of heating/cooling units via a plurality of passages corresponding to the heating/cooling units and that are configured to deliver the heat medium involved in heating or cooling performed by the heating/cooling units to the plurality of passages corresponding to the heating/cooling units respectively and to circulate the heat medium, and a plurality of heat medium flow switching devices (22, 23) that each are configured to perform switching so that one or a plurality of at least one heat medium in the plurality of passages corresponding to the heating/cooling units flow into and flow out of the corresponding use side heat exchanger, characterized in that the heat medium relay unit further includes a pressure absorber that is configured to connect to one of the plurality of passages, the pressure absorber alleviating a pressure change caused by a volumetric change of the heat medium, and a pressure equalizing pipe that is connected between the plurality of passages on inlet sides of the plurality of pumps disposed corresponding to the plurality of passages, or between the plurality of passages on outlet sides of the plurality of pumps disposed corresponding to the plurality of passages and is configured to eliminate a pressure difference caused by a temperature difference of the heat medium. indoor units including a plurality of use side heat exchangers that are configured to exchange heat between air with which heat is to be exchanged and a heat medium; and a heat medium relay unit including a plurality of heating/cooling units (15a, 15b) that are configured to heat or cool the heat medium, a plurality of pumps that are connected to the plurality of heating/cooling units via a plurality of passages corresponding to the heating/cooling units and that are configured to deliver the heat medium involved in heating or cooling performed by the heating/cooling units to the plurality of passages corresponding to the heating/cooling units respectively and to circulate the heat medium, and a plurality of heat medium flow switching devices (22, 23) that each are configured to perform switching so that one or a plurality of at least one heat medium in the plurality of passages corresponding to the heating/cooling units flow into and flow out of the corresponding use side heat exchanger, characterized in that a plurality of heating/cooling units (15a, 15b) that are configured to heat or cool the heat medium, a plurality of pumps that are connected to the plurality of heating/cooling units via a plurality of passages corresponding to the heating/cooling units and that are configured to deliver the heat medium involved in heating or cooling performed by the heating/cooling units to the plurality of passages corresponding to the heating/cooling units respectively and to circulate the heat medium, and a plurality of heat medium flow switching devices (22, 23) that each are configured to perform switching so that one or a plurality of at least one heat medium in the plurality of passages corresponding to the heating/cooling units flow into and flow out of the corresponding use side heat exchanger, characterized in that the heat medium relay unit further includes a pressure absorber that is configured to connect to one of the plurality of passages, the pressure absorber alleviating a pressure change caused by a volumetric change of the heat medium, and a pressure equalizing pipe that is connected between the plurality of passages on inlet sides of the plurality of pumps disposed corresponding to the plurality of passages, or between the plurality of passages on outlet sides of the plurality of pumps disposed corresponding to the plurality of passages and is configured to eliminate a pressure difference caused by a temperature difference of the heat medium.