A fire resistant shelter is provided which controls a temperature of an underground evacuation space in case of a long-lasting fire. A fire resistant shelter comprises a shelter main body, a water supply device, a heat insulating housing, and a drain device. The shelter main body is made of concrete having a thickness of 30 cm and is provided with an evacuation space therein. When a fire breaks out, an evacuee escapes to the evacuation space, closes an underground door, and subsequently opens a valve of a water supply pipe through a remote operation from inside the evacuation space. This supplies water to a heat-insulating space. When water being stored up to a level corresponding to the top end of the evacuation space is confirmed, the supply of the water is stopped. At that time, the water remains at a predetermined level in a ceiling water tank.