<；P>；PROBLEM TO BE SOLVED: To provide a water-treating technique in which an amount of energy consumed is small and which attains a high treating capacity. <；P>；SOLUTION: An apparatus for treating water is provided with: a bubble introducing vessel storing water to be treated； a plurality of bubble generators generating nano-bubbles or micro-nano-bubbles in the water to be treated in the bubble introducing vessel； a water treating vessel storing the water to be treated which contains the nano-bubbles or the micro-nano-bubbles, provided with an oxidation-reduction potential meter, and filled with a polyvinyl alcohol carrier； and a bubble generation control means operating or suspending the respective bubble generators based on the oxidation-reduction potential measured by the oxidation-reduction potential meter. <；P>；COPYRIGHT: (C)2010,JPO&INPIT
