Abstract: A heat accumulating type heating system and a heat energy storing method therefor which include improvements for heat accumulating, heat storage, heat preservation and use of heat by transferring electric power energy into heat energy in order to obtain an improvement for heating effects of the heating system, saving heat energy, and making a comfortable housing environment. The system has panels defining cavities thereon. Each panel is made of a sample heat accumulating material, and has a low heat conductivity (for example, in concrete or stone materials, 0.002KCalS.sup.-1 Cm.sup.-1 (.degree.C.)). Steam produced by heating water contained in the panel in the initial use is removed through a vent, and heat diffusion and convention in the airtight cavities are smoothly, efficiently achieved. Heat can be generated at night and stored.