PURPOSE: To facilitate the recovery of information in a power-off state by providing a segment area with a block containing defective information and inhibiting information transfer between the block and a cache area in normal access.

CONSTITUTION: Every segment of a magnetic bubble storage area is provided with a block such as the 8th block containing defective information which is discriminated by different flag information of the 1st loop, and information transfer between this 8th block and cache area is inhibited in normal access. When some segment is present in the cache area during initialization in power- on operation, defective information is erased in the cache area and stored to another storage element, only the information in the block 8 containing the defective information is transferred, and a segment address is read out to initialize a segment address counter. Then, the contents of the cache area and storage area are both recovered. In this case, even if the information in other storage elements are destroyed due to power-off operation, the information is recovered easily by the block 8 in the segment.