A method of error correction comprises error correction coding processing and interleaving and de-interleaving processings for digital subcoding data (as opposed to main data) in subchannels (as opposed to the main channel) to be transmitted. Apparatus is provided comprising means for performing those processings. The method comprises the steps of dividing digital subcoding data in one PACKET into a plurality of PACKs; adding a first redundant code for error detection or error correction to each of the PACKs; and interleaving the digital subcoding data in each of the PACKs and the first redundant code; whereby the interleaved data is transmitted together with frame sync signals and main data. The data in the subchannels is coded and interleaved and then recorded so that the distances between the data are maximized. Therefore, if errors should occur, the interpolation can be properly done, thereby improving the error correcting ability without requiring complicated error correction circuit or large buffer memory such as those required for the data in the main channel.