To deodorize garbage and save the labor of keeping it by providing a germ culture and mixing a plurality of soil germs in the culture bed and decomposing the garbage with this plurality of soil germs.

A germ culture B is filled in a casing 20 for decomposing kitchen garbage, and a porous inorganic substance is used as a material for this germ culture B. Furthermore, an example comprises a germ by decomposing a solid matter in the kitchen garbage into liquefied lower fatty acid, low molecular organic matter such as ketone, alcohol or the like, germs which are gasified by decomposing the liquefied matter into a carbon dioxide gas, methane gas or the like, and germs which are removed by decomposing malodor which is generated by a high protein such as meat, fish and the like into an amine. A panel heater 212 is installed on an outside surface of a bottom part 21 of a garbage decomposing casing 20, and this panel heater 212 maintains a temperature suitable to the culture of germ culture with a controller. Consequently, malodor from the germ culture B can be prevented.