VR EscapeSim is a simulator (Serious Game) that provides realistic fire scenes in virtual reality and allows the trainees to train themselves to escape the fire scene. This simulator has the following two features. First, body synchronization between user and avatar is supported using wearable devices (3D HMD, IMUs and EMGs). The second is a multi-user environment in which several users synchronized with the avatar can exercise together to escape. In the virtual space, users can not only see each other's images but also communicate through voice chat. I was in charge of the whole technical development of this project.