Additional information is transmitted by means of assigning a code to a particular scanning line in a VBI (vertical blanking interval). An initial value of a CRCC (Cyclic Redundancy Check Code) or a formula used to generate a CRCC is switched depending upon the type of additional information inserted in a data frame so that a difference in the initial value causes additional information other than CGMS-A (Copy Generation Management System-Analog) to be regarded as invalid, and thus the additional information does not cause an erroneous operation. However, CGMS-A has to be transmitted in the same manner in any country. To meet this requirement, the same initial value is used when CGMS-A is transmitted. This makes it possible to transmit data in a peculiar format without causing a problem regardless of a country in which transmission is performed. Besides, it is possible to transmit CGMS-A in the same manner regardless of the country.