The wave absorber composed of cylindrical bars arranged periodically and metallic mesh for improving visibility is proposed for ETC, and characteristics of reflectivity and shielding effect are evaluated analytically and experimentally. As a result, reflectivity of -10 dB and shielding effect of -25 dB are obtained for circularly polarized wave when the gap between cylindrical bars is 30 mm. Therefore, realization of proposed wave absorber for installing between ETC lanes can be clarified.