To perform a layout change for changing a container cargo stowage zone promptly without using a trailer.

With the use of a container crane formed so that a large-scale container 10A retained by a spreader 18 can pass through an interval between front and rear columns 14 vertically mounted to the front and rear of a sill beam 13, the large-scale container 10A in an existing cargo stowage zone is suspended by the spreader 18 and temporarily placed on a container cradle 24 placed on the sill beam 13. The container crane is made to travel from the existing cargo stowage zone to a new cargo stowage zone and stopped. The large-scale container 10A temporarily placed on the container cradle 24 is stowed at a predetermined position in the new cargo stowage zone.