An air conditioning apparatus comprising: an engine driven by combustion of fuel; an engine cooling system through which an engine cooling water for cooling down the engine flows; a radiator releasing a heat of the engine cooling water; a compressor actuated by the engine; an outdoor heat exchanger serving as a condenser for condensing a cooling medium, which is compressed by the compressor, while a cooling operation is carried out; an outdoor fan supplying a cooling air to the radiator and the outdoor heat exchanger in order to cool down the radiator and the outdoor heat exchanger; an expansion portion expanding the cooling medium, which is condensed by the outdoor heat exchanger while the cooling operation is carried out; an indoor heat exchanger serving as an evaporator for evaporating the cooling medium, which is expanded by the expansion portion, while the cooling operation is carried out; characterised by a control device controlling an actuation of the outdoor fan, wherein the control device includes a storage portion storing an information relating to a reference air volume corresponding to each degree of a rotation number of the compressor per unit time while the cooling operation is carried out as a plurality of levels; the control device selects and sets the level of the reference air volume corresponding to the rotation number of the currently actuated compressor per unit time among the plurality of the levels relating to the reference air volume stored within the storage portion while the cooling operation is carried out; and the control device adjusts the selected and set level of the reference air volume so as to increase or decrease the selected and set level of the reference air volume on the basis of a parameter of a difference (ΔT) between a condensing temperature at the condenser in a refrigeration cycle while the cooling operation is carried out and an ambient temperature and a parameter of a temperature (Te) of the engine cooling water. an engine driven by combustion of fuel; an engine cooling system through which an engine cooling water for cooling down the engine flows; a radiator releasing a heat of the engine cooling water; a compressor actuated by the engine; an outdoor heat exchanger serving as a condenser for condensing a cooling medium, which is compressed by the compressor, while a cooling operation is carried out; an outdoor fan supplying a cooling air to the radiator and the outdoor heat exchanger in order to cool down the radiator and the outdoor heat exchanger; an expansion portion expanding the cooling medium, which is condensed by the outdoor heat exchanger while the cooling operation is carried out; an indoor heat exchanger serving as an evaporator for evaporating the cooling medium, which is expanded by the expansion portion, while the cooling operation is carried out; characterised by a control device controlling an actuation of the outdoor fan, wherein the control device includes a storage portion storing an information relating to a reference air volume corresponding to each degree of a rotation number of the compressor per unit time while the cooling operation is carried out as a plurality of levels; the control device selects and sets the level of the reference air volume corresponding to the rotation number of the currently actuated compressor per unit time among the plurality of the levels relating to the reference air volume stored within the storage portion while the cooling operation is carried out; and the control device adjusts the selected and set level of the reference air volume so as to increase or decrease the selected and set level of the reference air volume on the basis of a parameter of a difference (ΔT) between a condensing temperature at the condenser in a refrigeration cycle while the cooling operation is carried out and an ambient temperature and a parameter of a temperature (Te) of the engine cooling water.