Abstract: A cyclonic type combustion apparatus that may be constituted so as to jet out a premixed gas made up of a mixture of a gaseous fuel and air into a cylindrical combustion chamber, from nozzle ports provided on an inside cylinder wall, the combustion apparatus being especially adapted for heating the liquid medium in hot water heaters, smoke tube boilers, and the like. For instance, a premixed gas obtained by mixing a gaseous fuel with air is jetted out into a cylindrical combustion chamber from a nozzle port opened on its inner peripheral surface along the inner peripheral surface in its tangential direction. The combustion chamber is disposed in a storage region containing heating medium water. The peripheral wall of the combustion chamber is constituted to be a heat conductive wall which is in contact with the heating medium water. The flame formed by the premixed gas jetted out from the nozzle port is cooled by the heating medium water.