In order to measure complementary hydrogen bonding between nucleobases, disulfide derivatives of thymine and adenine were newly synthesized. Surface Plasmon Resonance; SPR confirmed the formation of SAMs on Au. SPR shows that SAMs of nucleobase derivatives were completely formed within 60 minutes. Thickness of the adenine SAM and the thymine SAM is nearly the same. AFM tip was modified with the thymine SAM. The adenine SAM-modified Au electrode was clearly observed in an adhesion force map. The adhesion force between complementary nucleobases is larger than that of the non-complementary combination.