Emergency alert information is suitably transmitted by utilizing a broadcast service. A preamble section 31 of a transmission frame having a 100 ms interval includes a tuning data section 31A and a reserved bit section 31B, and is made up of a designated total bit length. The tuning data section 31A stores L1 data for tuning to a relevant broadcast channel on the receiving side. Also, the reserved bit section 31B inside the preamble section 31 stores emergency alert information processed by an emergency alert information processing unit 202. In a predetermined message mode, emergency alert information having a predefined message is expressed in a binary format and transmitted in just one frame.