A semiconductor memory has a plurality of blocks, and each of the blocks comprises a plurality of pages, and further, each of the pages has a plurality of memory cells. A block having defective bits less than N (N is an integer number more than 0) in all pages of the block stores a first data showing a normal block. A block including at least one page having defective bits more than N and including no page having defective bits more than M (M is an integer number of M>N) stores a second data showing a psedo-pass block as a pseudo-normal block. A block including at least one page having defective bits more than M stores a third data showing a defective block.