PURPOSE: To lower the specific fuel consumption of a rotary engine and to render the rotation smooth, by providing deflectors in the manner that a combustion recess formed in each flank of a rotor is divided into two parts in the direction of an eccentric shaft.

CONSTITUTION: A casing 3 consists of a rotor housing 1 having a two-node trochoidal inner surface and side housings 2. A triangular rotor 4 is turned eccentrically on the inside of the casing 3. Further, deflectors 10aW10c are provided in the manner of dividing combustion recesses 9aW9c formed in each flank 7aW7c of the rotor 4 into two sections in the direction of the eccentric shaft 6. With such an arrangement, it is enabled to stir up air-fuel mixture in a work chamber during compression stroke of the engine and to supply mixture sufficiently to the area near an ignition plug 13 located on the leading side of the work chamber. Further, it is enabled to obtain complete combustion of mixture on the trailing side 8b and to lower the specific fuel consumption of the engine.