An air-conditioning apparatus (100, 200, 100A) comprising: a first refrigeration cycle, in which a first compressor, a heat-source-side heat exchanger, a first expansion device (16a-16c), a first intermediate heat exchanger (15a, 15b), and a first passage of a heat exchanger for heating are connected through a first refrigerant pipe; and a second refrigeration cycle, in which a second compressor, a second passage of the heat exchanger for heating, a second expansion device, and a second intermediate heat exchanger are connected through a second refrigerant pipe, wherein a first refrigerant which is charged to the first refrigeration cycle and a second refrigerant which is charged to the second refrigeration cycle are each a zeotropic refrigerant mixture having different saturated gas temperatures and saturated liquid temperatures under a same pressure, wherein heat of the first refrigerant and heat of the second refrigerant are exchanged by the heat exchanger for heating, and wherein the heat exchanger for heating is connected to the first refrigerant pipe and the second refrigerant pipe so that the first refrigerant which is supplied to the first passage of the heat exchanger for heating and the second refrigerant which is supplied to the second passage flow counter to one another; the air-conditioning apparatus further comprises a controller, characterised in that the controller is configured to control an opening degree of the second expansion device so as to, when a first temperature difference is a difference between a saturated gas temperature of the first refrigerant at an inlet side and a saturated liquid temperature of the first refrigerant at an outlet side in the heat exchanger for heating, and when a second temperature difference is a difference between a saturated gas temperature of the second refrigerant at an outlet side and a temperature of the second refrigerant at an inlet side in the heat exchanger for heating, hold a difference between the first temperature difference and the second temperature difference in a predetermined value or less. a first refrigeration cycle, in which a first compressor, a heat-source-side heat exchanger, a first expansion device (16a-16c), a first intermediate heat exchanger (15a, 15b), and a first passage of a heat exchanger for heating are connected through a first refrigerant pipe; and a second refrigeration cycle, in which a second compressor, a second passage of the heat exchanger for heating, a second expansion device, and a second intermediate heat exchanger are connected through a second refrigerant pipe, wherein a first refrigerant which is charged to the first refrigeration cycle and a second refrigerant which is charged to the second refrigeration cycle are each a zeotropic refrigerant mixture having different saturated gas temperatures and saturated liquid temperatures under a same pressure, wherein heat of the first refrigerant and heat of the second refrigerant are exchanged by the heat exchanger for heating, and wherein the heat exchanger for heating is connected to the first refrigerant pipe and the second refrigerant pipe so that the first refrigerant which is supplied to the first passage of the heat exchanger for heating and the second refrigerant which is supplied to the second passage flow counter to one another; the air-conditioning apparatus further comprises a controller, characterised in that the controller is configured to control an opening degree of the second expansion device so as to, when a first temperature difference is a difference between a saturated gas temperature of the first refrigerant at an inlet side and a saturated liquid temperature of the first refrigerant at an outlet side in the heat exchanger for heating, and when a second temperature difference is a difference between a saturated gas temperature of the second refrigerant at an outlet side and a temperature of the second refrigerant at an inlet side in the heat exchanger for heating, hold a difference between the first temperature difference and the second temperature difference in a predetermined value or less.