PURPOSE: To use effectively a memory at a high speed and, at the same time, as a storage device having the large number of bits by constituting a storage circuit by connecting a prescribed number of storage elements in parallel and performing reading out and writing operations through a series-parallel converting circuit and parallel-serial converting circuit.

CONSTITUTION: A parallel-serial converting circuit 1 and series-parallel converting circuit 2 are respectively connected with a storage circuit 3, control circuit 4, and data bus 5. The storage circuit 3 is connected with the control circuit 4 and the control circuit is connected with an address bus 6. The circuit 3 is constituted in such a way that M pieces of storage elements of N pieces deep are connected in parallel in an L-bit width in the addressing direction. The converting circuit 1 supplies data of L×M×N bits on the data bus 5 to the M pieces of storage elements in parallel for N times after dividing the data into M pieces of blocks of every L×M bits. The circuit 2 reads out parallel data of L×M bits for N times from the storage circuit 3 and forms parallel data of L×M×N bits.