In this research, the water purification system using a photocatalyst was proposed and examination experimental about the effect and practical use possibility was performed. The titanium dioxide which is a photocatalyst is cheap, and exists abundantly as resources. The oxidization/reducing power which this titanium dioxide has are used for the purpose of decomposition removal of the quality of a water pollutant, and sterilization of a disease germ (typically estimated by coli form bacillus). Since the photocatalyst effect which a titanium dioxide has can provide the energy which advances an oxidation-reduction reaction by solar energy, it is energy saving very much in the point of not needing electric power using drained type resources. In old research, it was made difficult to use a photocatalyst for water disposal with many amounts of processing. So, in this research, while confirming the availability of solar energy, it inquired about the increase in the amount of water disposal by adopting the continuous processing method of a multilayer type. From the result of a batch type and a continuation type experiment, the validity of this method has been checked to the glucose which is model waste water, polluted river water, and all the object corruption water of sewage disposal water.