A filtration apparatus is provided which is easy to maintain, manage and which enables preservation of filtration characteristics due to the fact that filtration is carried out by use of a gelatinous filter apparatus. In the filtration apparatus, filtration characteristics can be maintained by providing a bubble supplying mechanism for removing a sedimentary layer comprising removables that is formed on a surface of a filtration film and a filtration characteristics restoring mechanism for restoring the filter film clogged by the removables by causing a back-flow of filtered water accumulated in a cistern. Filtration apparatus maintenance and management are facilitated by improving recovery efficiency of the precipitated removables by tapering a lower part inside a raw water tank and providing a recovery tank for recovering removables via a valve.