As a bio-molecular-sensor with high sensitivity using surface-enhanced Raman scattering (SERS), we developed two dimensional gold nano-mushroom arrays (G-NAMS). Because the heads of the gold mushrooms are closely placed over all aspects on a surface of substrate, a lot of SERS enable spot, so called "hot spots", are formed. . By using G-NAMS, we observed Raman signals of some bio samples. In the experiment to observe the adenine, which is one of four basis of the gene, dissolved in PBS solution, adenine concentrations of 5 pM could be detected. FDTD simulation indicated, that strong Raman enhancement of G-NAMS occurs due to synergistic action of the hot spots produced between metal nanoparticles, and the optical resonant effect in the alumina layer.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.