To solve problems that, since a conventional liquid decoration device is operated with an open state in a natural space, storage water is mixed with an impurity in air, water is gradually polluted and corrupted to damage a device, and feeling of beauty is spoiled; and since a sanitary issue such as propagation of harmful bacteria is concerned, maintenance is required, and precious time, labor and water are wasted.

An isolated chamber having a structure to suppress or intercept the inflow of air in a natural space by an enclosure material at least part of which is formed of a transparent plate is constructed to use a means for storing spring water to be used for water decoration and a component of a water decoration device necessary to carry out the water decoration in the isolated chamber. Further, a means for continuously supplying pure air into the isolated chamber by mounting a circulation fan inside or outside the isolated chamber as required to cause air in the isolated chamber to pass through a HEPA filter, a ULPA filter or the like to circulate it is used.