The present invention provides a Stirling engine capable of effectively recovering heat from exhaust gas flowing through a flue, and connecting a heating portion 10 and a regeneration portion 5 with each other through an operation gas tube without providing a flow passage separating portion 110, and the heating portion 10 includes a heating portion head 10a and a heat-transfer tube group, the heating portion head 10a includes first through holes 30R and second through holes 30S, the first through holes 30R are formed closer to a center region of the heating portion head 10a as compared with the second through holes 30S, one ends of U-shaped tubes are mounted in the first through holes 30R and the other ends of them are mounted in the second through holes 30S, and parallel exhaust gas flow passages is formed between the U-shaped tubes.