In this paper, we present electro-optic characteristics in cholesteric phase of the bimesogenic material with the helical twist power [HTP] agent BDH1218. The cholesteric phase of such mixture is more stable than blue phase and frequency-dependent in its alternative-current electric field response. It shows multi-stable-like domain structure characterized by the frequency and voltage applied. There are two driving methods for operation as a display. One is changing voltage under each of high and low frequency. The other is changing frequencies under a high voltage. We consider that the electro-optic characteristics of this cholecteric phase could be applied to electro-optic storage devices since all obtained gray levels are realized as memory states.