To contain a steel plate in a container and to store it kept in container on a storage rack.

This storage device comprises a steel plate storage building 3 in which sets of two lines of container storage racks are disposed in multiple rows and stages to face each other to form a container moving passage 5 between each other on a steel plate withdrawing yard 1, containers 4 to contain a steel plate 14 to be stored in the container storage rack 2, a ceiling crane 7 mounted along the steel plate storage building 3 capable of running along a rail 6 placed above the steel plate storage building 3, and a suspension beam 21 suspended from a trolley 20 laterally movable on the ceiling crane 7. The container 4 is suspended by the suspension beam 21, and an expansion spreader 8 having a container holding twist lock device 9 is provided at each of four corners to be laterally expanded and contracted, so the container 4 is delivered between a storage/delivery port on the ground and each container storage rack.