1. An error correction code (ECC) circuit comprising a Chien search unit configured to determine whether there is an error in each bit of a data sequence by using an arbitrary element on a Galois Field GF(2 m ), where m is an integer, as a substitution value of an error locator polynomial, wherein the Chien search unit, selects a coefficient of a nonlinear term from among terms of the error locator polynomial as a nonlinear coefficient; separates the error locator polynomial into a first location equation including only linear terms and a second location equation including only nonlinear terms; determines a third location equation by dividing the first location equation by the nonlinear coefficient; determines a fourth location equation by dividing the second location equation by the nonlinear coefficient; and determines whether there is an error for each of the bits by performing an XOR operation on a result of the third location equation using the substitution value and a result of the fourth location equation using the substitution value.