Photo-oxidation (photoelectrochromism) of poly(aniline) was performed using photoinduced electron transfer between Ru complex (Ru(bpy)(3)(2+)) and methylviologen molecules. Especially, effect of electrode structure on the photoelectrochromism was at first analysed in solution system. The electrode structure to increase the probability that poly(aniline) and Ru(bpy)(3)(2+) came into contact or very nearly so was effective to proceed the photoelectrochromism. Further, employment of poly(ethylene glycol) (PEG, Mw = 400) as additive into Flemion matrix revealed to enable the present photoelectrochromism even in all solid state. Effect of PEG addition was also discussed.