Surface potentials of three kinds of polymeric LB films deposited on Au, Cr and Al electrodes were measured at room temperature as a function of the number of deposited layers. The potential depended on the thickness of LB films and the work function of base electrode. The density of electronic state in LB films was determined. It was found that the electrostatic phenomena in LB films at metal/film interface are explained by assuming the presence of interfatial states in the region 1 nm from the interface and the distribution of the molecular orbital.