Abstract: A clean garment is provided with inherent identification data. A measuring part measures the cleanliness of the clean garment and outputs the obtained measurement data. An identification data input part reads the identification data of the clean garment and outputs it as an identification data. At least the previous measurement data is stored in a data base in association with the identification data. A signal processing part receives the measurement data and identification data. In the signal processing part, the previous measurement data of the clean garment is read from the data base based on the received identification data C, to calculate the difference (increment) between the now obtained measurement data and the previous measurement data, and the obtained difference is referenced to a predetermined criterion, to judge the cleanliness of the clean garment. The cleanliness of clean garments can be managed per clean garment by a clean garment managing system.