The present technology relates to a data processing device and a data processing method so that an LDPC code with a good bit error rate is provided.An LDPC encoder encodes by an LDPC code whose code length is 16200 bits and code rate is 10/15. The LDPC code includes information bits and parity bits. A parity check matrix H includes an information matrix part corresponding to the information bits of the LDPC code and a parity matrix part corresponding to the parity bits. The information matrix part of the parity check matrix H is represented by a parity check matrix initial value table that indicates a position of an element 1 of the information matrix part for each 360 columns. The present technology is applicable to a case in which LDPC encoding and LDPC decoding are performed.