Photochemical grafting of ferrocene to Si was investigated in a vinylferrocene solution in tetrahydrofuran, diethyl ether, or dibutyl ether. The grafting of vinylferrocene onto a Si(111) surface was carried out by placing a hydrogen-terminated Si(111) substrate into a vinylferrocene-solvent solution and illuminating the substrate with visible light. The samples prepared in vinylferrocene-diethyl ether and vinylferrocene-dibutyl ether solutions yielded ferrocene-terminated Si(111) and the oxidation states of Fe were mainly +2. On the other hand, a polymerized vinylferrocene layer was formed on the samples treated in the vinylferrocene-tetrahydrofuran solution and the oxidation states of Fe were +3. In addition, the dibutyl ether-prepared sample showed a cleaner surface than that of the diethyl ether-prepared sample.