The present invention provides an air cooling device of an integrated thermo-hygrostat, which is advantageous over known integrated thermo-hygrostats in that it is possible to prevent indoor air from being mixed with cold outdoor air when cooling an indoor space using the cold outdoor air in winter by installing an indoor air control damper which can control the flow of the indoor air in front of an evaporator installed in an inner portion of a main body. The air cooling device can rapidly lower the temperature of the indoor space to the intended temperature, increase cooling efficiency, and prevent power from being unnecessarily consumed by being capable of suspending the cooling function thereof when cooling is performed using outdoor air having a temperature below a predetermined temperature.