A data-processing device includes a plurality of data generation units, a plurality of bit change number calculation units, a bit change number comparison unit, a first data selection unit, and a bit-coupling unit. The data generation unit arranges input data to generate first conversion data based on each prescribed arranging method. The bit change number calculation unit compares values of respective bits in the first conversion data output at the n-th time and the (n+1)-th time by the corresponding data generation unit, and calculates a bit number based on the comparison result as a bit change number. The bit change number comparison unit compares values of the respective bit change numbers, selects the data generation unit, and outputs selection information. The first data selection unit outputs any one first conversion data selected based on the selection information as selection data. Then, the bit-coupling unit couples the selection information.