The invention relates to bio water purifier which improves the structure of water molecular and changes the water to weak alkali drinker. The invention comprises a sediment filter removing rust and floating matters in the water, a precarbon filter removing chlorine and impurities in the water, a ceramic material tube improving the water molecule, maximizing movement of the water molecule and making weak alkali water by radiating far infrared ray, a silver carbon filter removing odor and bacteria in the water and activating the water, and a ceramic filter removing various harmful matters in the water.