[Problem] To provide a small size combustion apparatus which reduces the amount of harmful exhaust gas such as nitrogen oxides and realizes high-temperature combustion gasification with high efficiency in multiple stages, and a combustion method therefor. [Solution] The combustion apparatus according to the present invention is formed from a cylindrical member on the base side and a tapered member on the distal end side, and comprises, on the distal end side, a fuel charge section into which a gas-liquid mixed fuel is sprayed and charged, and comprises, on the base side, a flame discharge section, the combustion apparatus being characterized by comprising: a plurality of heat exchangers as described above which are arranged in parallel at a desired distance such that the axis of a tubular body extends from the distal end side to the base side; a plurality of combustion chambers formed in front of and behind the plurality of heat exchangers; an air pipe for introducing outside air into an arbitrary combustion chamber; and a return pipe for returning carbon dioxide generated by combustion, from at least one downstream combustion chamber to an upstream combustion chamber, among the plurality of combustion chambers.