To obtain a thermal decomposition reaction furnace which can increase the efficiency of heat transfer, smoothly excludes metal wares such as wires, electric wires, chains and the like and allows an easy maintenance.

This furnace is equipped with a plurality of coaxially arranged cylindrical heaters 29 having the inner path for passing the waste material (a) inside the partition wall 30 of a cylindrical shape for transferring heat to the waste material (a) and having the outer path 32 for passing heated air (i) outside the partition wall 30. In addition, the outer path 32 of the cylindrical heater 29 is divided into a plurality of small paths which are formed in spirals around the circumference of the partition wall 30.