In accordance with embodiments, a server room managing air conditioning system includes: a first coil; a second coil; and an air supply fan. The first coil adjusts returned air of a server room to a predetermined temperature value lower than a supplied air temperature target value and dehumidifies the returned air. The second coil adjusts the returned air of the server room to a predetermined temperature value higher than the supplied air temperature target value so that the supplied air temperature target value and a supplied air humidity target value can be achieved when the returned air is mixed with air adjusted by the first coil. The air supply fan mixes the returned air and supplies the mixed returned air as the supplied air to the server room.