PURPOSE: To enable the direct reforming and purifying of water of lakes, ponds, etc., by floating a water quality reforming and purifying device body by floats, disposing this body like a floating island on water and disposing a float structural body which floats on the water while exhibiting functions of water quality reforming and purifying and is capable of exhibiting functions exclusive of the purposes for water quality reforming and purifying.

CONSTITUTION: This floating type water quality reforming and purifying device 32 consists of a septic tank, a mechanical chamber and the floats. This mechanical chamber is internally provided with a reforming original liquid storage tank, a pH control original liquid storage tank and a strainer to adequately provide the temp. range suitable for culture of natural purifying bacterial growing in the water of lakes, ponds and rivers, etc., in the septic tank of the purifying device and a range of adequate pH and various other environmental conditions so that the conditions for living of all living things are provided. The natural purifying bacteria are propagated in the reforming septic tank of the water quality reforming and purifying device so that the reformed and purified water in the state of sufficiently propagating the natural purifying bacteria is returned into the external rivers, etc. The form of the natural island is obtd. in spite of the artificial island so that bird and fishes can live and trees can grow.