The invention relates to an internal combustion engine comprising a rotor which is mounted in such a way that it can be rotated about a central axis in a housing, and in which cylinders are arranged in the same plane, pistons being introduced into said cylinders, the inner end of said pistons being connected to an eccentrically arranged axis in an articulated manner. The cylinders are rotatably mounted in the outer edge of the rotor respectively with the outer ends thereof, and end in the outer envelope of the rotor. At least one combustion chamber is arranged in the housing, the inner end of the chamber ending in the inner housing wall that surrounds the outer envelope of the rotor. The combustion chamber is arranged at an angle of between 45 and 90 degrees, especially between 70 and 85 degrees, to the radius of the rotor.