A multi type air conditioner comprising: a plurality of indoor units (21, 22, 23, 24), each comprising an indoor heat exchanger (211, 221, 231, 241); and a plurality of outdoor units (11, 12, 13, 14) connected to the plurality of indoor units (21, 22, 23, 24), each comprising an outdoor heat exchanger (130, 200, 210, 220), wherein, when a defrosting operation condition is satisfied during a heating operation, the plurality of outdoor units (11, 12, 13, 14) successively perform a defrosting operation, wherein each of the plurality of outdoor units (11, 12, 13, 14) comprises a four-way valve, and during the heating operation, the outdoor heat exchanger (130, 200, 210, 220) of each of the plurality of outdoor units (11, 12, 13, 14) is configured to serve as an evaporator by switching a refrigerant flow through the four-way valve, and the outdoor heat exchanger (130, 200, 210, 220) in which the defrosting operation is performed is configured to serve as a condenser by switching the refrigerant flow through the corresponding four-way valve, wherein the outdoor heat exchanger (130, 200, 210, 220) is divided into a plurality of heat exchanger parts (131, 132) through which a refrigerant separably flows, and when a specific outdoor unit of the plurality of outdoor units (11, 12, 13, 14) performs the defrosting operation, frost on the whole heat exchanger parts (131, 132) of the specific outdoor unit is removed, characterized in that each of the outdoor units (11, 12, 13, 14) comprises a plurality of four-way valves (121, 122), and the number of four-way valves (121, 122) is equal to that of heat exchanger parts (131, 132). a plurality of indoor units (21, 22, 23, 24), each comprising an indoor heat exchanger (211, 221, 231, 241); and a plurality of outdoor units (11, 12, 13, 14) connected to the plurality of indoor units (21, 22, 23, 24), each comprising an outdoor heat exchanger (130, 200, 210, 220), wherein, when a defrosting operation condition is satisfied during a heating operation, the plurality of outdoor units (11, 12, 13, 14) successively perform a defrosting operation, wherein each of the plurality of outdoor units (11, 12, 13, 14) comprises a four-way valve, and during the heating operation, the outdoor heat exchanger (130, 200, 210, 220) of each of the plurality of outdoor units (11, 12, 13, 14) is configured to serve as an evaporator by switching a refrigerant flow through the four-way valve, and the outdoor heat exchanger (130, 200, 210, 220) in which the defrosting operation is performed is configured to serve as a condenser by switching the refrigerant flow through the corresponding four-way valve, wherein the outdoor heat exchanger (130, 200, 210, 220) is divided into a plurality of heat exchanger parts (131, 132) through which a refrigerant separably flows, and when a specific outdoor unit of the plurality of outdoor units (11, 12, 13, 14) performs the defrosting operation, frost on the whole heat exchanger parts (131, 132) of the specific outdoor unit is removed, characterized in that each of the outdoor units (11, 12, 13, 14) comprises a plurality of four-way valves (121, 122), and the number of four-way valves (121, 122) is equal to that of heat exchanger parts (131, 132).