A refrigeration apparatus comprising a plurality of outdoor units (10, 20), an indoor unit (61, 65), a refrigerant circuit and a control unit (7, 10a, 20a, 61a, 65a), the plurality of outdoor units (10, 20) being connected in parallel to the indoor unit (61, 65), the refrigerant circuit being capable of executing at least an air-warming operation and comprising in a connected configuration: an indoor heat exchanger (62, 66) provided to the indoor unit (61, 65); and outdoor heat exchangers (13, 23), compressors (11, 21), and switching valves (12, 22) provided to the respective outdoor units (10, 20), wherein when a predetermined defrosting condition is fulfilled during execution of the air-warming operation, the outdoor unit (7, 10a, 20a, 61a, 65a) selectively executes either: an alternating defrost mode in which an operation, which is performed with the switching valves having been connected such that at least one of the outdoor heat exchangers (13, 23) of the plurality of outdoor units (10, 20) is caused to function as evaporator while one or more outdoor heat exchangers of the rest of the plurality of outdoor units (10, 20) is caused to function as condenser by being designated as component to be defrosted, is executed while switching the outdoor heat exchanger (13, 23) to be defrosted; or a reverse-cycle defrost mode executed with the switching valves having been connected such that the outdoor heat exchangers (13, 23) of the outdoor units are caused to function as condensers and the indoor heat exchanger (62, 66) is caused to function as an evaporator, characterized in that when the predetermined defrosting condition having been fulfilled, the control unit (7, 10a, 20a, 61a, 65a) selectively executing the reverse-cycle defrost mode when a predetermined outflow condition pertaining to an outflow integrated quantity of refrigerator oil has also been fulfilled and selectively executing the alternating defrost mode when the predetermined outflow condition has not been fulfilled. an indoor heat exchanger (62, 66) provided to the indoor unit (61, 65); and outdoor heat exchangers (13, 23), compressors (11, 21), and switching valves (12, 22) provided to the respective outdoor units (10, 20), wherein when a predetermined defrosting condition is fulfilled during execution of the air-warming operation, the outdoor unit (7, 10a, 20a, 61a, 65a) selectively executes either: an alternating defrost mode in which an operation, which is performed with the switching valves having been connected such that at least one of the outdoor heat exchangers (13, 23) of the plurality of outdoor units (10, 20) is caused to function as evaporator while one or more outdoor heat exchangers of the rest of the plurality of outdoor units (10, 20) is caused to function as condenser by being designated as component to be defrosted, is executed while switching the outdoor heat exchanger (13, 23) to be defrosted; or a reverse-cycle defrost mode executed with the switching valves having been connected such that the outdoor heat exchangers (13, 23) of the outdoor units are caused to function as condensers and the indoor heat exchanger (62, 66) is caused to function as an evaporator, characterized in that when the predetermined defrosting condition having been fulfilled, the control unit (7, 10a, 20a, 61a, 65a) selectively executing the reverse-cycle defrost mode when a predetermined outflow condition pertaining to an outflow integrated quantity of refrigerator oil has also been fulfilled and selectively executing the alternating defrost mode when the predetermined outflow condition has not been fulfilled. an alternating defrost mode in which an operation, which is performed with the switching valves having been connected such that at least one of the outdoor heat exchangers (13, 23) of the plurality of outdoor units (10, 20) is caused to function as evaporator while one or more outdoor heat exchangers of the rest of the plurality of outdoor units (10, 20) is caused to function as condenser by being designated as component to be defrosted, is executed while switching the outdoor heat exchanger (13, 23) to be defrosted; or a reverse-cycle defrost mode executed with the switching valves having been connected such that the outdoor heat exchangers (13, 23) of the outdoor units are caused to function as condensers and the indoor heat exchanger (62, 66) is caused to function as an evaporator, characterized in that when the predetermined defrosting condition having been fulfilled, the control unit (7, 10a, 20a, 61a, 65a) selectively executing the reverse-cycle defrost mode when a predetermined outflow condition pertaining to an outflow integrated quantity of refrigerator oil has also been fulfilled and selectively executing the alternating defrost mode when the predetermined outflow condition has not been fulfilled.