In this paper, we propose a low cost motion capture system for personal computer-based immersive virtual environment (PIVE) system. Existing desktop virtual environment systems, which are generally less realistic than workstation-based immersive virtual environment (WIVE) systems, typically rely on general purpose input devices such as mouse and keyboard for interacting with a three-dimensional virtual environment. However, since the devices such as mouse and keyboard are machine-centered, these kinds of input devices don't suit immersive virtual environment. After developing PIVE systems by simplifying components in conventional immersive virtual environment systems, we propose here low cost devices for capturing human motion to express human behavior in the virtual environment. The system is composed of HMD, data glove, and sensor units, and gives the motion information of human which includes head motion, each finger's motion, arm motion, and legs motion. The proposed system offers expandability and compatibility in contrary to existing WIVE. We will show that the proposed low cost input device is implemented to the example in which user move around inside of and interact with virtual office reality wearing data glove and HMD.