An air-conditioning apparatus comprising: at least one controller ; an outdoor unit including a compressor , a first refrigerant flow path switching device , and a heat-source-side heat exchanger ; a heat medium relay unit including an intermediate heat exchanger , an expansion device , a second refrigerant flow path switching device , and a pump ; and at least one indoor unit including a use-side heat exchanger , wherein the compressor , the first refrigerant flow path switching device , the expansion device , the second refrigerant flow path switching device , and the intermediate heat exchanger are connected using a refrigerant pipe, thereby making up a refrigeration cycle (A) in which a refrigerant circulates, the intermediate heat exchanger and the use-side heat exchanger are connected using a heat medium pipe , thereby making up a heat medium circulation circuit (B) in which a heat medium different from the refrigerant circulates, the controller is configured to switch the first refrigerant flow path switching device to execute a defrost operation mode in which a refrigerant discharged from the compressor is supplied to the heat-source-side heat exchanger , and characterized in that during the defrost operation mode, part of a refrigerant flowing out from the heat-source-side heat exchanger is supplied to the intermediate heat exchanger without passing through the expansion device , and rest of the refrigerant is returned to the outdoor unit without passing through the expansion device and the intermediate heat exchanger . at least one controller ; an outdoor unit including a compressor , a first refrigerant flow path switching device , and a heat-source-side heat exchanger ; a compressor , a first refrigerant flow path switching device , and a heat-source-side heat exchanger ; a heat medium relay unit including an intermediate heat exchanger , an expansion device , a second refrigerant flow path switching device , and a pump ; and an intermediate heat exchanger , an expansion device , a second refrigerant flow path switching device , and a pump ; and at least one indoor unit including a use-side heat exchanger , wherein the compressor , the first refrigerant flow path switching device , the expansion device , the second refrigerant flow path switching device , and the intermediate heat exchanger are connected using a refrigerant pipe, thereby making up a refrigeration cycle (A) in which a refrigerant circulates, the intermediate heat exchanger and the use-side heat exchanger are connected using a heat medium pipe , thereby making up a heat medium circulation circuit (B) in which a heat medium different from the refrigerant circulates, the controller is configured to switch the first refrigerant flow path switching device to execute a defrost operation mode in which a refrigerant discharged from the compressor is supplied to the heat-source-side heat exchanger , and characterized in that during the defrost operation mode, part of a refrigerant flowing out from the heat-source-side heat exchanger is supplied to the intermediate heat exchanger without passing through the expansion device , and rest of the refrigerant is returned to the outdoor unit without passing through the expansion device and the intermediate heat exchanger . <EOS>