A multi-air conditioner for heating/cooling operations, including at least one indoor unit for heating/cooling operations including an indoor heat exchanger; and an outdoor unit for heating/cooling operations including a compressor, an outdoor heat exchanger, and a switching unit configured to be disposed in a discharge side of the compressor to switch a flow of refrigerant. The outdoor unit includes a receiver that selectively stores refrigerant or oil according to a cooling or heating operation mode and provides the stored refrigerant or oil to the compressor. Accordingly, in the accumulator of the multi-air conditioner using the receiver, the receiver which is not used in the heating mode may be converted and used for oil storage, thereby preventing oil burnout without adding structure.