It is useful to simulate disaster situations by reconstructing actual buildings in a virtual space to enable people using the buildings to learn how to act in a disaster situation before it occurs. Therefore, we are developing a disaster-simulation system that simulates various disaster situations by virtually reproducing the situation inside buildings to allow individuals to experience disaster situations by using the latest virtual reality (VR) system. We use a mobile robot equipped with a laser-range sensor that measures the distance to objects in a building, an RGB depth camera to collect distance and image data while the robot automatically travels along a route suitable for 3D measurement, and a 4K panoramic image camera that captures high-quality color data. The robot can also scan physical objects individually by moving around it automatically. We then arrange the objects in a 3D map and manipulate them. We have also developed a VR system called “Building-Scale VR” that consists of indoor 3D maps filled with manipulable virtual objects that we call “operation targets” and a VR headset capable of position tracking within the building. In this talk, we explain how to implement Building-Scale VR and its applications to disaster simulations. It is useful to express disaster situations by reconstructing actual buildings into virtual space and enable users in the building to experience such situations beforehand to learn how to properly act during a disaster.