To provide a magnetic water purifying agent which treats water containing impurities, especially the water containing chlorine or bleaching powder and emitting an offensive odor to provide tasteless, odorless, and sterilized drinking water and has excellent deodorizing action and antibacterial action.

The magnetic water purifying agent is obtained by baking a mixture, which is composed of 1-15 mass% of tourmaline, 1-15 mass% of mica and 70-98 mass% of magnetic clay, under a reducing atmosphere.