Abstract: A container electronic seal device and a method of operating the container electronic seal device are provided. The container electronic seal device is installed on a door locking rod and a lock handle provided in a container door. The apparatus includes a body unit, a locking arm unit, and an electronic parts unit. The body unit is disposed around part of the door locking rod and part of the lock handle, and is provided with a through hole, a guide opening, and an access port. The locking arm unit rotates and fastens the lock handle inserted into the guide opening of the body unit. The electronic parts unit selectively performs locking and unlocking depending on whether a security authentication file of the external memory is normal and monitors illegitimate opening. The container electronic seal device is selectively locked and unlocked using the external memory storing a security authentication file.