A data processing apparatus may include a data conversion unit that arranges the input data in each transfer data in the conversion unit using one transfer data as one transfer unit and a predetermined number of transfer units as one conversion unit when converting a plurality of input data input sequentially into transfer data having a bit number identical to a predetermined bit number of a data bus and sequentially transferring the converted transfer data. The data conversion unit may include a data generation unit and a first data arrangement changing unit. The first data arrangement changing unit may include a bit change number calculating unit, a bit change number analysis unit, a first data sorting unit, and a data coupling unit.