Abstract: An internal combustion engine includes a turbocharger and an upstream pipe. The turbocharger includes a compressor housing and a compressor wheel. The compressor wheel includes main blades and a shaft. The shaft extends parallel to the rotation axis of the compressor wheel. The main blades each project from the shaft in a direction orthogonal to the rotation axis. The main blades are spaced apart from one another in the circumferential direction. The upstream pipe includes a tubular member and guide vanes. The guide vanes each project from the inner wall surface of the tubular member. The guide vanes are spaced apart from one another in the circumferential direction. The number of the guide vanes is a prime number greater than two times the number of the main blades.