Recently, immersive projection technology (IPT) systems such as CAVE and CABIN have attracted great attention. In IPT systems, since we can experience virtual environments with whole body, these can provide high immersive virtual environments. To interact with virtual environments easily, IPT systems often adopt one-handed input systems. However, by using bimanual input systems, their operationality, e.g., walking-through and pointing, can be improved. Although there are several bimanual input systems for virtual environments, these have not been used for IPT systems. In this paper, we propose a bimanual input system for IPT systems. In our proposed system, users wear compact joysticks on both hands and their hands? positions are detected by magnetic sensors. By using the system, users can interact with the virtual environment in the IPT system. From our evaluations, we confirmed that our proposed system provides fast and easy operations in virtual environments.