Abstract: Provided are a container security device, a container security system, and a security management method which efficiently check opening/closing of a container door and an opening/closing record of the container door and process seal information, cargo state information, base passing information, and location tracking information in real-time from a gate-out process from a shipper (POA) to a gate-in process to a consignee (POD). The container security system includes the container security device which includes a first communication means for providing container seal information through multi-channel communication; and a second communication means for providing information about container transportation and storage in real-time.