PURPOSE: To perform uniform heating of a heater pipe by means of combustion gas so as to improve heat transfer efficiency by arranging the exhaust gas port of a combustion chamber to the vicinity of the lower part of the combustion chamber, in a combustion device for a hot gas engine wherein a heater pipe is arranged in a combustion chamber and an expansion cylinder and a heat accumulator housing coupled thereto.

CONSTITUTION: Fuel injected from a burner 1 and air for combustion fed through an air swirler 2 are mixed together in a combustion chamber 3 for combustion. Thereafter, heat is imparted to a heater pipe 4 by generated combustion gas which is exhausted through an exhaust gas port 8. Heat imparted to the heater pipe 4 is transferred to an expansion cylinder 6 and a heat accumulator housing 7. In this constitution, the exhaust gas port 8 is arranged to the vicinity of the lower part of the combustion chamber 3. This constitution causes the flow, as shown by an arrow mark B, combustion gas throughout a range of from the inner upper part to the inner lower part of the combustion chamber 3 to perform uniform heating of the heater pipe 4. Thus, the combustion heat of combustion gas can be transferred to working gas in the heater pipe 4 with high efficiency.