PURPOSE: To improve the quality of activated water by bringing raw water into contact with a far-IR radiator or treating the water at least under the influence of the radiator to diminish the molecule group of the water in size.

CONSTITUTION: Raw water is repeatedly passed through a far-IR radiator of the activated water producing device to obtain a water with the molecule group diminished in size. The water in a storage tank 2 is firstly brought into contact with ozone from an ozonizer 6 and influenced therein by the radiator to obtain the water with the molecule group diminished in size. For this purpose, the water storage tank 2 and a far-IR radiator-packed vessel 4 are connected through water pipelines 5, a circulating pump 3 and the ozonizer 6 are provided to the one pipeline 5, and ozone is supplied to the vessel 4 along with water.