Air-quality conditioning device

An air-quality conditioning device is proposed, which can be singly used or used in combination with a small air conditioner. In an enclosed space, concentration of carbon dioxide is detected by a carbon dioxide concentration detecting module (10) of the device. While the detected concentration of carbon dioxide reaches a predetermined upper limit value, an air conditioning mechanism (30) is driven by an air-conditioning controlling module (20) for introducing external fresh air to the space. While the carbon dioxide concentration reduces to a predetermined lower limit value, the air conditioning mechanism is driven for stopping the introduction of the external air. Therefore, the carbon dioxide concentration can be properly adjusted in the space so as to maintain good air quality therein.