A block cipher ARIA substitution apparatus, the apparatus includes a first Sbox operation unit for performing operations of a substitution box S1 and a substitution box S1−1; a second Sbox operation unit for performing operations of a substitution box S2 and a substitution box S2−1; and a control unit for determining modes of the first Sbox operation unit and the second Sbox operation unit. The first Sbox operation unit has a first inverse affine transformation unit for performing an inverse affine operation for obtaining S1−1; a finite field inverse element operation unit for computing an inverse element of GF(28) or a result value of the first inverse affine transformation unit; a first affine transformation unit for performing an affine operation for obtaining S1; and a first and a second multiplexer.