An air conditioning apparatus comprising a refrigerant circuit in which a plurality of indoor units (40, 50, 60), respectively comprising an indoor heat exchanger (42, 52, 62) and an indoor expansion mechanism (41, 51, 61), are connected to an outdoor unit, including an outdoor expansion mechanism, via a connection pipe, the air conditioning apparatus individually controlling each of the indoor units (40, 50, 60) to operate or stop, the air conditioning apparatus further comprising: a control unit that, when at least one of the indoor heat exchangers (42, 52, 62) functions as a radiator, controls an opening degree of the indoor expansion mechanism and an opening degree of the outdoor expansion mechanism; characterized by a determination unit that determines whether a refrigerant amount in the refrigerant circuit is appropriate (i) by using an opening degree ratio of the opening degree of the indoor expansion mechanism (41, 51, 61) to the opening degree of the outdoor expansion mechanism as an amount of change corresponding to a change in state of a refrigerant between the indoor expansion valve (41, 51, 61) and the outdoor expansion valve, and/or (ii) on the basis of a temperature of a connection pipe between the indoor expansion mechanism (41, 51, 61) and the outdoor expansion mechanism as an amount of change corresponding to a change in state of a refrigerant between the indoor expansion valve (41, 51, 61) and the outdoor expansion valve, wherein each of the indoor expansion mechanisms (41, 51, 61) is connected in series to the outdoor expansion mechanism via the connection pipe. a control unit that, when at least one of the indoor heat exchangers (42, 52, 62) functions as a radiator, controls an opening degree of the indoor expansion mechanism and an opening degree of the outdoor expansion mechanism; characterized by a determination unit that determines whether a refrigerant amount in the refrigerant circuit is appropriate (i) by using an opening degree ratio of the opening degree of the indoor expansion mechanism (41, 51, 61) to the opening degree of the outdoor expansion mechanism as an amount of change corresponding to a change in state of a refrigerant between the indoor expansion valve (41, 51, 61) and the outdoor expansion valve, and/or (ii) on the basis of a temperature of a connection pipe between the indoor expansion mechanism (41, 51, 61) and the outdoor expansion mechanism as an amount of change corresponding to a change in state of a refrigerant between the indoor expansion valve (41, 51, 61) and the outdoor expansion valve, (i) by using an opening degree ratio of the opening degree of the indoor expansion mechanism (41, 51, 61) to the opening degree of the outdoor expansion mechanism as an amount of change corresponding to a change in state of a refrigerant between the indoor expansion valve (41, 51, 61) and the outdoor expansion valve, and/or (ii) on the basis of a temperature of a connection pipe between the indoor expansion mechanism (41, 51, 61) and the outdoor expansion mechanism as an amount of change corresponding to a change in state of a refrigerant between the indoor expansion valve (41, 51, 61) and the outdoor expansion valve, wherein each of the indoor expansion mechanisms (41, 51, 61) is connected in series to the outdoor expansion mechanism via the connection pipe.