PURPOSE: To reduce the dimension and weight of the engine and permit the actual use of the ceramic engine by reciprocating a part in the lateral direction inside an outer wall formed from a column and the fan-shaped parts and converting said movement to a revolution movement by a crankshaft.

CONSTITUTION: An outer wall is formed by connecting a column and a fan- shaped part, and a part 5 having a revolution shaft 6 at the center is arranged inside the outer wall. The lateral reciprocating movement of the part 5 is converted to a revolution movement by a crankshaft 9. A cam shaft 10 is driven by the half revolution speed of that of the crankshaft 9. The part 5 is reciprocated in the lateral direction by allowing combustion chambers 1-4 to explode in succession. Therefore, the simple structure is obtained, and the small-sized and lightweight engine can be obtained.