PURPOSE: To enable operating gas to be heated efficiently to a high temperature, by providing a heater tube, through which a compression chamber communicates with an expansion chamber, and inserting pipes into a part, faced to a flame side of the heater tube, so that a heat receiving area of the operating gas increases.

CONSTITUTION: A Stirling engine 1 of dual type has four cylinders 2, and an expansion chamber 3 in each cylinder 2 communicates with a compression chamber 7 of the neighboring cylinder 2 through a heater tube 4, heat accumulator 5 and a cooler 6. And the Stirling engine 1 reciprocates a working piston 8 by reciprocating operating gas between the expansion chamber 3 and the compression chamber 7. In the above constitution, a plurality of pipes 13 are additionally provided by nickel brazing or the like in the first part 11 in a flame side of the heater tube 4. And radiation heat of a flame, received by the first part 11, is applied to also the pipes 13 inside the first part. In this way, operating gas, increasing its heat receiving area, is heated efficiently to a high temperature.