To quickly and inexpensively decompose dibenzofuran which is a kind of environmental hormone, with high decomposition rate and efficiency by decomposing the dibenzofuran with a thermophilic bacterium having dibenzofuran decomposing ability.

The dibenzofuran a kind of the environmental hormone, that is the endocrine disruptor is decomposed by culturing the thermophilic bacterium [e.g.; bacillus-sp. JF8 (FERMBP-6098) or the like] having dibenzofuran decomposing capabilities, in a thermophilic bacterium culturing medium, separating the cultured fungus body from the culture solution after culturing, adding the fungus body to a liquid including dibenzofuran, and maintaining at the growth temperature of the thermophilic bacterium. The processor is capable of downsizing, shortening the processing time, and improving the processing efficiency because the rate of decomposition of this thermophilic bacterium is rapid, and capable of simplifying disinfection to inhibit contamination, reducing the cost of the decomposing processor for culturing at high temperature.