An object is to provide a sorting device, a selecting system, a sorting method, and a program capable of preventing a decrease in processing speed and an increase in the number of processing steps. The sorting device includes a rank computation device (101) that performs, in parallel, comparisons of numerical data Dk (k is an integer from 0 to n−1) included in numerical data D0 to Dn-1 (n is an integer of 1 or more) with each of the numerical data D0 to Dn-1 excluding the numerical data Dk, and computes a rank indicating a value level of the numerical data Dk in the numerical data D0 to Dn-1 by using each comparison result, and a selection device (102) that rearranges the numerical data D0 to Dn-1 in order on the basis of ranks of the numerical data D0 to Dn-1.