An LDPC iteration decoder includes a second interleaver for performing interleave processing on a signal series outputted from a soft output detection unit, an LDPC decoder for implementing LDPC decoding processing on a signal that has undergone interleave processing; a checking unit for checking that an error has been corrected by the LDPC decoder; a second de-interleaver for performing sort processing the reverse of the second interleaver on a signal that has been LDPC decoded; a judging unit for judging whether to carry out iteration processing again; and a DAE for computing a likelihood again, in cases in which iteration decoding is carried out, and giving feedback to the front stage of the second interleaver.