An air conditioning system for processing a sensible heat load and a latent heat load of a target space to the extent required, and adjusting a temperature and humidity of the target space to target levels, the air conditioning system comprising: a cooling heat exchanger for circulating a heating medium for cooling air blown into the target space, causing heat exchange between the heating medium and the air, and cooling and dehumidifying the air; a heater for heating the air cooled and dehumidified by the cooling heat exchanger; a blower fan for creating a flow of the air blown into the target space through the cooling heat exchanger and the heater; and a control unit having a quantity of cooling adjusting unit configured to adjust a quantity of cooling supplied from the heating medium to the air in the cooling heat exchanger, a quantity of heating adjusting unit configured to adjust a quantity of heating supplied from the heater to the air, and a blown air flow volume adjusting unit configured to adjust an air flow volume supplied by the blower fan, the blower fan being a fan in which a speed of rotation can be varied in stages of the speed of rotation, and characterized in that the control unit being configured to find the quantity of cooling and the quantity of heating required to process the sensible heat load and latent heat load requirement of the target space to the extent required at each stage of the speed of rotation of the blower fan, and adjust the quantity of cooling, the quantity of heating, and the supplied air flow by selecting a combination in which the supplied air flow is the lowest from among combinations of the quantity of cooling, the quantity of heating, and the supplied air flow capable of processing the sensible heat load and latent heat load requirement of the target space to the extent required. a cooling heat exchanger for circulating a heating medium for cooling air blown into the target space, causing heat exchange between the heating medium and the air, and cooling and dehumidifying the air; a heater for heating the air cooled and dehumidified by the cooling heat exchanger; a blower fan for creating a flow of the air blown into the target space through the cooling heat exchanger and the heater; and a control unit having a quantity of cooling adjusting unit configured to adjust a quantity of cooling supplied from the heating medium to the air in the cooling heat exchanger, a quantity of heating adjusting unit configured to adjust a quantity of heating supplied from the heater to the air, and a blown air flow volume adjusting unit configured to adjust an air flow volume supplied by the blower fan, the blower fan being a fan in which a speed of rotation can be varied in stages of the speed of rotation, and characterized in that the control unit being configured to find the quantity of cooling and the quantity of heating required to process the sensible heat load and latent heat load requirement of the target space to the extent required at each stage of the speed of rotation of the blower fan, and adjust the quantity of cooling, the quantity of heating, and the supplied air flow by selecting a combination in which the supplied air flow is the lowest from among combinations of the quantity of cooling, the quantity of heating, and the supplied air flow capable of processing the sensible heat load and latent heat load requirement of the target space to the extent required. a heater for heating the air cooled and dehumidified by the cooling heat exchanger; a blower fan for creating a flow of the air blown into the target space through the cooling heat exchanger and the heater; and a control unit having a quantity of cooling adjusting unit configured to adjust a quantity of cooling supplied from the heating medium to the air in the cooling heat exchanger, a quantity of heating adjusting unit configured to adjust a quantity of heating supplied from the heater to the air, and a blown air flow volume adjusting unit configured to adjust an air flow volume supplied by the blower fan, the blower fan being a fan in which a speed of rotation can be varied in stages of the speed of rotation, and characterized in that the control unit being configured to find the quantity of cooling and the quantity of heating required to process the sensible heat load and latent heat load requirement of the target space to the extent required at each stage of the speed of rotation of the blower fan, and adjust the quantity of cooling, the quantity of heating, and the supplied air flow by selecting a combination in which the supplied air flow is the lowest from among combinations of the quantity of cooling, the quantity of heating, and the supplied air flow capable of processing the sensible heat load and latent heat load requirement of the target space to the extent required.