An internal combustion engine includes an exhaust manifold, a main exhaust passage, an auxiliary exhaust passage, a communicating passage, a first switching mechanism, and a second switching mechanism. The main exhaust passage is connected to the exhaust manifold. The auxiliary exhaust passage is connected to the main exhaust passage. The communicating passage connects with the main exhaust passage and the auxiliary exhaust passage. The first switching mechanism switches a communication state of the exhaust manifold among a first state, a second state, and a third state. The second switching mechanism switches a communication state of the communicating passage with the main exhaust passage among a fourth state, a fifth state, and a sixth state.