This paper proposes a nonverbal interface system using bio-potential signals, such as EOG and EMG, measured by a brain-computer interface and investigates its possibility of applying to control application. A simple gesture recognition algorithm is presented to estimate the user's intentions from the EOG and EMG signals, and the user's emotion is evaluated by using the EEG signal. To evaluate the feasibility and the characteristics of the nonverbal interface system, moving control experiments in 3D virtual space are carried out and the effectiveness of the proposed interface system is confirmed