Various types of interface devices operated with the hands have been developed and are widely used. However, we use our legs for walking in the real world, so it is natural to use an interface devices operated with the legs for moving around a virtual environment. In this paper, we have developed a new interface device “Waraji (WAlking, Running, And Jumping Interface)”. Using Waraji, users can work at ease in a virtual environment because their hands are free from movement operations. In addition, because Waraji is smaller than other interfaces for movement, it can he easily worn. Experiments have shown that Waraji provides operationality similar to that of a joystick. It will be useful for surround-display virtual-environment systems such as CAVE (CAVE Automatic Virtual Environment).