Specular reflection from polyaniline films is in-situ studied as a function of potential. Intensity of the reflected 633 nm light of He-Ne laser is low for the neutral film, but it increases drastically by oxidizing the polymer film. Upon further oxidation, the reflectance decreases greatly. The initial rise of reflectance is ascribed to a transition from diffuse reflection to specular reflection resulting from a conformational change of polyaniline. The decay of reflectance at higher potentials is accounted for in terms of absorption of the 633 nm light due to oxidized polyaniline film. Time course of reflectance changes induced by stepping of the potential is also investigated.