The present invention is particularly applied to serial concatenated coding and serial concatenated trellis coded modulation. In second encoding 107, which is inner coding, a sequence that is not encoded or that is encoded so as to produce a finite impulse response and a sequence that is encoded so as to produce an infinite impulse response are output. In interleaving 106 before the second encoding 107, the sequences are permuted so as not to be mixed with each other.