Abstract: The waste burning boiler comprises a cylindrical outer wall, a cylindrical inner wall consisting of a plurality of vertical water pipes having the gaps therebetween closed by plate members. The plate members are provided with a plurality of holes communicating the annular chamber between the inner and outer walls with the combustion chamber defined inside the inner wall. Compressed air is introduced into the annular chamber, and is blown into the combustion chamber from these small holes. The air blown from these holes provide a sufficient amount of oxygen for combustion, and raises the combustion temperature. Additionally, the air flow from the small holes provide a favorable stirring effect which improves the transfer of heat produced by combustion to the water pipes.