Anodic polarization curve is measured to evaluate the condition of passivated film on steel surface. Normally, polarization curve can be adapted only to "specimen" immersed in aqueous solution in laboratory. Furthermore, a set of measurement takes about 40 minutes. It makes difficult to apply this measurement for actual structures. If these difficulties could be overcome, polarization curve measurement can be used on site to evaluate the condition of paasivated film on steel surface in concrete. In this study, at first, a new measuring method with new sensor system, which makes it possible to apply it to actual structures, was developed. And, several factors were tested to evaluate their effects on polarization curve. Finally, several conclusions could be obtained. (1) Polarization curve obtained with new sensor system is almost equal to it with ordinary system. (2) Polarization speed affects on polarization curve, as that the current flow is increased with high polarization speed. (3) With new sensor system, polarization curve measurement can be adopted to actual structures on site.