A data processing apparatus which receives a code word of a Low Density Parity Check, LDPC, code as prescribed in the DVB-S.2 standard ETSI EN 302 307 V1.1.2, transmitted thereto in an interleaved form as symbols each formed from m, m ≥ 2, code bits, wherein the LDPC code word is generated in accordance with a parity check matrix, the parity check matrix comprising an information matrix and a parity matrix, the information matrix, which corresponds to the information bits of the LDPC code having an information length of K bits, has a cyclic structure and the parity matrix, which corresponds to the parity bits of the LDPC code having a parity length of M bits, has a staircase structure, and wherein plural ones of the code bits of the LDPC code word which correspond to a value 1 included in one arbitrary row of the parity check matrix are not included in the same symbol, the data processing apparatus comprising: a demapping means for carrying out demapping by converting the symbols of the received LDPC code word into code bits, and a reverse re-arrangement means for carrying out a reverse re-arrangement process which is a reverse re-arrangement corresponding to a re-arrangement process of the LDPC code word, such that plural ones of the code bits of the LDPC code which correspond to a value 1 included in one arbitrary row of the parity check matrix are not included in the same symbol, wherein the reverse re-arrangement means carries out column twist deinterleaving by writing code bits of the received LDPC code word in the row direction into a store for storing mb bits in the row direction and N/(mb) bits in the column direction, where b is a predetermined positive integer and N is the LDPC code length, and by changing the reading out starting position with regard to one or more of a plurality of columns when reading out the code bits of the received LDPC code word in the column direction; and an LDPC decoding means for carrying out LDPC decoding of the received LDPC code word for which the reverse re-arrangement process is carried out using a conversion parity check matrix obtained by carrying out column replacement for the parity check matrix corresponding to a parity interleaving, wherein the parity interleaving interleaves the K+qx+y+1th code bit from among the parity bits which are the K+1th to K+Mth code bits of the LDPC code word to the position of the K+Py+x+1th code bit, K + M = N, x being an integer higher than 0 but lower than P and y being an integer higher than 0 but lower than q, where P = 360 and q = M/360. a demapping means for carrying out demapping by converting the symbols of the received LDPC code word into code bits, and a reverse re-arrangement means for carrying out a reverse re-arrangement process which is a reverse re-arrangement corresponding to a re-arrangement process of the LDPC code word, such that plural ones of the code bits of the LDPC code which correspond to a value 1 included in one arbitrary row of the parity check matrix are not included in the same symbol, wherein the reverse re-arrangement means carries out column twist deinterleaving by writing code bits of the received LDPC code word in the row direction into a store for storing mb bits in the row direction and N/(mb) bits in the column direction, where b is a predetermined positive integer and N is the LDPC code length, and by changing the reading out starting position with regard to one or more of a plurality of columns when reading out the code bits of the received LDPC code word in the column direction; and an LDPC decoding means for carrying out LDPC decoding of the received LDPC code word for which the reverse re-arrangement process is carried out using a conversion parity check matrix obtained by carrying out column replacement for the parity check matrix corresponding to a parity interleaving, wherein the parity interleaving interleaves the K+qx+y+1th code bit from among the parity bits which are the K+1th to K+Mth code bits of the LDPC code word to the position of the K+Py+x+1th code bit, K + M = N, x being an integer higher than 0 but lower than P and y being an integer higher than 0 but lower than q, where P = 360 and q = M/360.