In order to clarify effects of UV irradiation on Surface electric states of insulating polymers, measurements of contact potential difference by Kelvin method and measurements of valence band spectrum by XPS were carried out. Charge transfer range was observed at metal-insulating polymer interface. Charge transfer range of PVK (polyvinyl carbazole) and PVP (poly-2-vinyl pyridine) were about 165 nm and 55nm, respectively. The Fermi level of PVK became higher with UV irradiation. On the other hand, the Fermi level of PVP became lower with UV irradiation.The changes of Fermi level are considered to be due to oxidation and morphological change.