To develop a functional beverage from funori polysaccharide containing funoran, we investigated the removal of arsenic in funori and the optimal extraction condition to reduce the high viscosity. Among the various pre-treatment methods tested, the arsenic in funori material was removed the most effectively by ethanol washing. The viscosity of the polysaccharide extract by heating with citrate was remarkably reduced and resulted in a significant increase in the content of polysaccharide, funoran. From these results, a technology of processing the functional beverage containing funoran was established.