SUPERCHARGER

PROBLEM TO BE SOLVED: To provide a supercharger with a simple configuration and a high supercharging effect.SOLUTION: A first vane 52 of a turbine 50 is formed into a plate-like shape on an outer wall of a first cylinder part 51 to extend from one end toward the other end of the first cylinder part 51. A second cylinder part 53 is positioned inside one end of the first cylinder part 51, and connected to a compressor 20 via a shaft 12 on one end side. A second vane 54 is formed into a plate-like shape to extend from one end to the other end of the second cylinder part 53 while connecting an inner wall of the first cylinder part 51 and an outer wall of the second cylinder part 53. An exhaust air introduction port 55 is formed into an annular shape between one end of the first cylinder part 51 and one end of the second cylinder part 53, so as to introduce exhaust air between the first cylinder part 51 and the second cylinder part 53. An exhaust air flow passage 56 is formed inside the first cylinder part 51 between the other end of the first cylinder part 51 and the other end of the second cylinder part 53, so that the exhaust air introduced from the exhaust air introduction port 55 can be circulated.