Abstract: A supercharged rotary piston engine, which comprises a cylinder (1) with fluid conducting inlet and outlet channels (15, 16); an inner chamber (2) of the cylinder being ring-shaped. The inner chamber includes a supercharging section (10), a working stroke section (11) and an exhaust section (12). A main shaft (5) is rotatably positioned in the cylinder, and a rotary piston (3) in the inner chamber (2) is mounted coaxially with the main shaft (5) and is connected to and rotatable together with the main shaft (5) for driving the shaft. At least one stop valve (8) is disposed between the inlet and outlet channels, the stop valve sealingly closing the inner chamber when in the closed position, and the stop-valve when in the open position leaving the inner chamber free for the unhindered passage of the rotating piston. A supercharger (K) for supercharging fluid under a final compression pressure is disposed in the supercharging section (10) of the inner chamber (2) behind the rotating piston (3).