PURPOSE: To store data in a couple of storage MOS transistors (TRs) at once by providing a couple of MOS TRs to a memory cell, outputting the difference of signals so as to eliminate the erasure before writing of a couple of MOS TRs.

CONSTITUTION: The program to the storage MOS TRs P1, P2 is applied by applying a high electric field between the gate and the drain. The high electric field is bipolar and the write is applied when, e.g., the gate is at a high level and the drain is at a low level, and erasure is applied when the gate is at a low level and the drain is at a high level conversely. In using one of bit lines BL, the inverse of BL as a positive potential and the other as a 0 potential, one of the TRs P1, P2 is in the erasure state and the other is in the write state. At read, the word line WL is brought into a high level to detect a relative potential difference of the TRs P1, P2 by a differential amplifier 2. Thus, a reciprocal signal is inputted to a couple of bit lines to complete the programming to the storage element at once.