To reduce stress level of an exhaust manifold and reduce vibration stress accompanying up-and-down direction vibration of a supercharger by increasing rigidity and support strength of a supercharger support structure without causing increase of the number of components of a supercharger support structure and increase of assembly man-hour.

The exhaust manifold provided with: a branch part connected to each exhaust port of a cylinder head; a collecting part collecting the branch parts; and an exhaust part connected to the collecting part and attached to the supercharger, is provided with a reinforcement part connecting a supercharger side flange part formed on the exhaust part and a cylinder head side flange part abutting on a cylinder head of the branch part opposing to the supercharger.