To favorably discharge gas internally present in a device during filling of a bone filling material, a bone treatment system has a shaft that has a flow path which enables a bone filling material to be placed on a space of a radius to flow therethrough, and a filling balloon that communicates with the flow path in a distal portion of the shaft and that is filled with the bone filling material. Furthermore, the bone treatment system includes a gas discharge portion that causes air (gas) inside the flow path to flow in a direction toward a proximal end rather than the filling balloon, when the bone filling material is supplied to the flow path.
