Abstract: Disclosed is a heat-accumulating material comprising a thermally inert max which is an open-porosity substance, and a thermosensitive working substance which is a hygroscopic substance capable of reversible dehydration-hydration processes. A heat-accumulating material according to the present invention is intended for the use as a cooling and heating agent for a gas/air atmosphere, a thermostating agent, and as protection against heating of articles and building constructions, for example radio-electronic devices, as well as as a means for fire extinguishing.