PROBLEM TO BE SOLVED: To prevent occurrence of problems caused by combustion residue (residue generated in combustion) of a solid fuel in an internal combustion engine in which power is generated by burning the solid fuel in a combustion chamber.SOLUTION: A cylinder 14 having a combustion chamber 18 is integrally rotatably disposed on an assembled rotary body 13 disposed rotatably on a crank shaft 12, and the assembled rotary body 13 (combustion chamber 18) is rotated and driven by a motor so that centrifugal force is generated. A fuel supply pipe 15 for supplying a solid fuel from a rotation center side of the combustion chamber 18 into the combustion chamber 18, is disposed to forcibly move and supply the solid fuel from the rotation center side into the combustion chamber 18 by the centrifugal force due to the rotation of the assembled rotary body 13. Further an exhaust port 22 is disposed at a rotation outer peripheral side of the combustion chamber 18 to discharge combustion residue of the solid fuel, the combustion residue of the solid fuel is forcibly moved to the rotation outer peripheral side of the combustion chamber 18 and discharged from the exhaust port 22 by the centrifugal force due to the rotation of the assembled rotary body 13.