The present invention discloses a cleanroom for storing glass substrates. The cleanroom includes an outlet disposed on a bottom of the cleanroom. A cleaning unit is arranged on a ceiling of the cleanroom and which provides a cleaned, ionized air flow so as to eliminate a static electricity and airborne particles accumulated over a surface of a glass substrate. In addition, the present invention further provides a cleaning unit. An ionized airflow is generated so as to remove the airborne particles and static electricity accumulated over the glass substrate. It features an excellent performance, and therefore increases the yield of the product.