PURPOSE: To reproduce correctly the adjacent 1st and 2nd cycles by increasing or decreasing one of the polarity inverting cycles of the 1st and 2nd cycles so that the change of the polarity inverting cycle is previously compensated in a recording mode.

CONSTITUTION: The change of the polarity inverting cycle due to a peak shift phenomenon is previously compensated only in case such codes are recorded that codes '1' and '0' are turned continuously into '10' or '01' and the polarity inverting cycle is discontinuous. For this purpose, both polarity inverting cycles of adjacent cycles T and T/2 are increased or decreased for a fixed period of time TP. Thus cycles (T+TP) and (T/2-TP) are recorded and therefore the cycles T and T/2 can be reproduced in a reproduction mode. Then the codes can be delivered with no error.