PURPOSE: To provide a heat accumulation type cooling and heating device which uses midnight electric power and permits the reduction of the size of its heat accumulating tank and of the installation cost.

CONSTITUTION: A heat accumulation type cooling and heating device is provided with an absorption refrigerator 2 for performing cooling or heating operation and a heat accumulating tank 1 for accumulating heat energy as power source for the absorption refrigerator, the heat accumulating tank 1 is provided in its interior with an electric heater 22 and a heat transfer pipe 21 and is packed with magnesia as a heat accumulating material 23 and the heat energy is supplied to the absorption refrigerator 2 using a fluid undergoing gas-liquid phase change in a heating medium being passed through the heat transfer pipe 21.