Fluorescence anisotropy of green fluorescent protein (GFP) molecule, immobilized on the surface of quartz substrate as single molecular layer, was measured for application to nano-probing of local environment. GFP has fluorescence without any additional prosthetic group or metal atom. It has protective structure against the outer environment. For use of nano-probe of local environment, fluorescence anisotropy of GFP was measured as it is immobilized on quartz substrate. By comparison with back ground scattering, fluorescence anisotropy of GFP was measured with higher fidelity. The anisotropy value suggests rather free rotational motion of GFP in tethered state on the substrate.