PURPOSE: To store data which differ in the number of bits in one memory element by utilizing the capacity of the memory element to the utmost.

CONSTITUTION: An error detecting and correction code selecting circuit 10 generates an error detection code and an error detection correction code according to the state of a mode control signal Mo. The error detection code and error detection correction code are different in the number of bits, so data to which the error detection code and error detection correction code are added are also different in the number of bits. When the bit constitution of a memory matrix and the number of bits of data to be stored are different, the bits of the data to be stored are shifted by a bit shift circuit 12 and inputted to the memory matrix 14. The address changes as a result of the bit shift, so an address calculating circuit 16 calculates a new address and designates it to the memory matrix 14. Consequently, even when the bit constitution of the memory and the number of bits of data to be stored are different, the memory can effectively be utilized to the utmost without generating any free space in the memory area.