A flash memory is made to store a same boot program in a plurality of blocks in it. When a flash memory controller receives an access command for accessing the storage region storing the boot program from a CPU (Step S101), it outputs the read out data to the CPU only when the corresponding block is not faulty according to the determination (Steps S105, S106) made on the basis of the ECC contained in the data read out from the corresponding page and the determination (Step S109) made on the basis of the block information also contained in the data read out from the corresponding page. If, on the other hand it is determined that the block is faulty, the flash memory controller reads out the boot program stored in the next block (Steps S106, S103) and determines once again that the block is faulty or not faulty.