The inventive concept provides a substrate treating apparatus. The substrate treating apparatus includes a process chamber configured to treat a substrate; a transfer assembly configured to transfer the substrate to the process chamber; and a diagnosis unit configured to detect an abnormal state of the transfer assembly, and wherein the transfer assembly comprises: a housing having a transfer space; and a transfer robot configured to transfer the substrate to the process chamber, and wherein the diagnosis unit comprises: a detection member for detecting an air vibration generated within the housing; and a diagnosis member for diagnosing a driving unit of the transfer assembly based on the air vibration detected by the detection member.