: Today, it has become very popular to represent 3D CG models onto the screen of a workstation or personal computer. In almost all software that displays 3D models, users can control their viewpoint of projection with pointing devices such as a mouse or trackball. However it is not intuitive to control the viewpoint with such devices, because there is an insufficient degree of freedom. Although locating viewpoint needs 6 degrees of freedom (3 degrees in position, and 3 degrees in direction), off-the-shelf pointing devices are basically two-dimensional controllers. We propose a 3D model viewer with a real-time user’s face tracking system. This system provides an easy method to make observations of 3D models from any direction and to any scale that users may choose.