Reproducibility and Operationality are used evaluation indices in bilateral control systems. Reproducibility shows degree of reproduction of the environmental impedance in master robot. Operationality shows degree of operation force which human operator feels obstacle force besides environmental impedance. In conventionally, operational force is equal to operationality. However, if system is non-ideal condition such as disturbance modeling error in Reaction Force Observer (RFOB), estimated force will be different from true value. In this condition, operational force is different from operationality. Therefore, in this paper, operational force in non-ideal condition is considered. From experimental bode diagram results, operational force in non-ideal condition was made performance of bilateral control degradation.