An air-conditioning apparatus (100, 100A), comprising: a refrigerant circuit that connects a compressor, a first refrigerant flow switching device, a heat source side heat exchanger, a plurality of first expansion devices, and refrigerant side passages of a plurality of heat exchangers related to heat medium by refrigerant pipes, with a temperature sensor (35b, 35d) disposed between the heat exchanger related to heat medium (15a, 15b) and the first expansion device, the refrigerant circuit circulating a heat source side refrigerant; a heat medium circuit that connects a pump, a use side heat exchanger, and heat medium side passages of the plurality of heat exchangers related to heat medium by heat medium pipes, the heat medium circuit circulating a heat medium; one ore more controllers; characterized in that the heat source side refrigerant and the heat medium exchanging heat in each of the heat exchangers related to heat medium while flowing in parallel to each other such that, when the heat exchanger related to heat medium is functioning as an evaporator, on the inlet side the heat medium with high temperature and the refrigerant with low temperature exchange heat, such that while approaching the outlet side, the temperature of the heat medium is reduced and the temperature of the refrigerant is increased, wherein a zeotropic refrigerant mixture, in which a saturated liquid refrigerant temperature is lower than a saturated gas refrigerant temperature under a same pressure condition, is used as the heat source side refrigerant, and the one or more controllers are configured, when at least one of the heat exchangers related to heat medium is functioning as an evaporator, to estimate the occurrence of heat medium freezing by setting a positive value larger than zero as a freezing temperature correction value and setting a value obtained by subtracting the freezing temperature correction value from the detection temperature of the temperature sensor as an anti-freezing temperature, where the freezing temperature correction value is set as a value obtained by multiplying a coefficient by the temperature difference between the saturated gas refrigerant temperature and the saturated liquid refrigerant temperature, or as a value obtained by multiplying a weighting coefficient by the saturated gas refrigerant temperature and the saturated liquid refrigerant temperature. a refrigerant circuit that connects a compressor, a first refrigerant flow switching device, a heat source side heat exchanger, a plurality of first expansion devices, and refrigerant side passages of a plurality of heat exchangers related to heat medium by refrigerant pipes, with a temperature sensor (35b, 35d) disposed between the heat exchanger related to heat medium (15a, 15b) and the first expansion device, the refrigerant circuit circulating a heat source side refrigerant; a heat medium circuit that connects a pump, a use side heat exchanger, and heat medium side passages of the plurality of heat exchangers related to heat medium by heat medium pipes, the heat medium circuit circulating a heat medium; one ore more controllers; characterized in that the heat source side refrigerant and the heat medium exchanging heat in each of the heat exchangers related to heat medium while flowing in parallel to each other such that, when the heat exchanger related to heat medium is functioning as an evaporator, on the inlet side the heat medium with high temperature and the refrigerant with low temperature exchange heat, such that while approaching the outlet side, the temperature of the heat medium is reduced and the temperature of the refrigerant is increased, wherein a zeotropic refrigerant mixture, in which a saturated liquid refrigerant temperature is lower than a saturated gas refrigerant temperature under a same pressure condition, is used as the heat source side refrigerant, and the one or more controllers are configured, when at least one of the heat exchangers related to heat medium is functioning as an evaporator, to estimate the occurrence of heat medium freezing by setting a positive value larger than zero as a freezing temperature correction value and setting a value obtained by subtracting the freezing temperature correction value from the detection temperature of the temperature sensor as an anti-freezing temperature, where the freezing temperature correction value is set as a value obtained by multiplying a coefficient by the temperature difference between the saturated gas refrigerant temperature and the saturated liquid refrigerant temperature, or as a value obtained by multiplying a weighting coefficient by the saturated gas refrigerant temperature and the saturated liquid refrigerant temperature.