STORAGE DEVICE

PURPOSE:To secure high security with simple configuration by enabling access to a user memory by performing access to an address only the user of a storage means for access limit can recognize. CONSTITUTION:Data are stored in the specified address of a memory 50 for access limit, and data not coincident to any address are stored in the other addresses at random. In the case of performing access from a main system through an input/output terminal 58 and memories 51-54 for users, the specified address of the memory 50 for access limit is read, these data are inputted to terminals P0-P3 and A1-A4 of an address comparator 56, the output of a terminal Y at the address comparator is turned to L, and an address coder 55 can be operated. In this case, access to the memories 51-54 for users is enabled. Namely, the access to the memories 51-54 for users can not be performed without reading the data stored at the specified address of the memory 50 for access limit, and high security can be secured.