Due to the strong alkalinity of the healthy concrete environment, a protective passivation film is formed on the surface of rebar and corrosion of the rebar is suppressed. However, there is a problem that rebars in concrete are corroded by external factors and the structure deteriorates. In order to understand the corrosive state of the rebar, it is necessary to grasp the surface condition of the rebar in concrete. Corrosion state of the rebar in concrete can be evaluated by measuring the electrochemical impedance. However, when the passive film is formed, the impedance describes only part of semicircle on the Nyquist plane, and it may be difficult to determine the passive film resistance. In this study, we evaluated the corrosive environment of rebars in concrete from admittance analysis with probe electrodes which are embedded in concrete. When the passive film was formed, a semicircle was observed in the admittance spectrum transformed from the impedance measurement results, and the film resistance could be obtained from the low frequency limit. In addition, probe electrodes were embedded in the concrete structure of viaduct of the Tokaido Shinkansen, and the corrosive state of rebar in concrete was investigated by using admittance analysis.