PURPOSE: To realize the free recording, reproducing and erasing of signals, by forming a ferrodielectric layer on a semiconductor layer.

CONSTITUTION: A relative shift is given among a semiconductor layer 11, a ferrodielectric layer 12 and a lead wire recording head 14 to which the information to be recorded is applied over the layer 12. Thus the layer 12 is selectively polarized in a prescrived direction to record an information signal 15. The above-mentioned actions are performed by a recording medium. In addition to this means, a reproducing means is provided to relatively shift a conductive reproducing head 18 along a recording track on which the information signal is recorded through the above- mentioned recording medium and then detect the change of the electrical properties of the layer 11 caused by the recorded information signal to reproduce the information signal.