In recent years, technology of brain-computer interface (BCI) has been developed. One application of BCI is for entertainment, that is, BCI game. As ideas in science fictions, BCI game has potential extensibility in combination with virtual reality environment. However, implementation and evaluation of the combination have not been studied well. Thus in this study, we proposed the BCI game system composed of a simple EEG recorder, a smart tablet, a PC, and a immersive head mounted display. We conducted experiments and evaluate our hypothesis that the head mounted display (3D condition) is suitable for BIC game comparing with a flat display (2D condition). Results of a statistical analysis showed that beta/alpha ratio, which was used for controlling the game, in the 3D condition was significantly higher than one in the 2D condition. The results of questionnaires showed that 3D condition were superior to the 2D condition. In sum, we concluded that the immersive head mounted display is suitable for combining with BCI games.