PURPOSE: To ensure accurate data word synchronism even if dropout or the like occurs by inserting periodically a data synchronizing signal in one horizontal scanning line in each field.

CONSTITUTION: A digital data such as sound information is inserted to a prescribed part in one field of a video format signal. The data synchronizing signal deciding the periodic timing is inserted just before said digital data. Moreover, the data synchronizing signal is inserted periodically in at least one horizontal scanning line in this field. Thus, even if the data synchronizing signal recorded just before the digital data is missing due to the dropout or the like in this way, the succeeding reading of the digital data is read accurately.