PURPOSE: To secure the assured recording and reproduction for the code data via one unit of the magnetic head by recording the NRZ data on the low coercive force track with shift of 1/2 cycle to the clock recorded previously on the high coercive force track of the tape and then giving the simultaneous reproduction.

CONSTITUTION: The hardly erasable clock recorded previously on track 2 of the high coercive layer of the magnetic tape is read out through magnetic head 4 and then changed into the reproduction clock with the 1/2 cycle shifted through clock signal phase shift circuit 34 comprising FM demodulator 31, mono-multi 34A and edge detection circuit 34B each. With this reproduction clock, the encoded data of memory 25 is controlled, and then the code data is recorded in the NRZ system on track 1 of the low coercive force layer of the tape via FF26, gate circuit 27, writing circuit 28 and head 4 each and in synchronization with the clock with the 1/2 cycle shifted. Then the FM modulation signal corresponding to the data is obtained through the simultaneous reproduction. Thus the assured recording and reproduction is ensured for the data by the hardly erasable clock and via one unit of the head.