This virtual reality system is very useful to represent and analyze complex physical simulation result. But it is very difficult to control virtual objects (represented numerical simulation data) with a general input device in Immersive Projection Technology like CAVE system, since such an input device has less function than a keyboard and we cannot remember the every procedure to control many virtual objects. A voice control is very suitable to control in a virtual reality space. So we appended a speech recognition system to virtual reality system: CompleXcope. In this paper, we explain about our virtual reality system, the method to link the virtual reality system and the speech recognition system, which can recognize unspecified person's voice, and practicability of this system.