Interleaving/deinterleaving method and apparatus

An interleaving/deinterleaving method and apparatus may interleave/deinterleave first data to produce second data so that the arrangement of data elements of the second data is different from that of the first data. To accomplish this, word data that are part of the first data are read from a data storage section and a data element to be processed is selected from the word data for output. The operations of reading word data and selecting data elements of the word data to output are repeated, and a sequence of data elements to be processed at the time of repetition is determined in accordance with the arrangement of the data elements of the second data.