To provide a heating mechanism which is good in heat efficiency and is reduced in fuel cost and expenses for decomposing organic garbage.

In a treating device for decomposition and extinction of garbage discharged from various facilities such as a household, a restaurant and a food processing and manufacturing plant, a plate-shaped heating device 3 filled with an antifreezing fluid 5 in the inner space and provided with heat pipes 4 passing through the antfreezing fluid 5 is surface-jointed onto the wall of a decomposing vessel 2.