A water purification solid material of relatively low cost whose handling is easy, produced from a natural raw material only; and a method of water purification with the use of the same. There is provided a water purification solid material for use in water purification using a microbe, characterized in that it is obtained by working only a natural raw material whose main component is a polysaccharide. Further, there is provided a method of water purification with the use of the same.