Method and apparatus for transmitting an information signal generate a plurality of block signals on the basis of the information signal, generate a plurality of parity block signals on the basis of the plural data block signals, generate a frame signal containing the plural data block signals and the parity block signals, and send out the frame signal. Each of the data block signals includes a first block synchronizing signal indicating the start of the data block signal, a data signal containing the information signal and a first parity signal derived by encoding the data signal. Each of the parity block signals incudes a second block synchronizing signal indicating the start of the parity block signal, a second parity signal and a third parity signal. Bit signals located at same bit positions in the respective second parity signals are derived by encoding bit signals located at the same positions in the respective data signals. Bit signals located at same bit positions in the respective third parity signals are derived by encoding the bit signals located at the same bit positions in the respective first parity signals or alternatively the third parity signal in each parity block signal is derived by encoding the second parity signal in each parity block signal.