PURPOSE: To obtain a water activator for purifying water with enhanced activation effect and capable of being provided inexpensively by screening primary granulated matter composed of diatomaceous earth to produce seed particles and secondarily granulating these seed particles and subjecting the secondary granules to primary and secondary baking processes at specific temps.

CONSTITUTION: Diatomaceous earth is dried and ground to a 50 mesh or less and the ground diatomaceous earth is granulated using water to obtain primary granules which are, in turn, screened to produce seed particles. Next, these seed particles are secondarily granulated using water by a granulator heated to 30-60°C and the secondary granules are dried. Subsequently, these secondary granules are primarily baked at 150-250°C for 10-20hr and succeedingly secondarily baked at 600-900°C) for 4-24hr to produce a required water activator. The water activator is reduced in water molecule group (cluster) and discharges various minerals and minor elements and emits far infrared rays. Therefore, the water activator can be enhanced in water activating action and can be inexpensively produced.