Abstract: An intake manifold is provided with a chamber member provided with an exhaust port and a chamber formed therein, a port member provided with an intake groove forming a ventilation passage bent so as to be communicated with the exhaust port and the chamber of the chamber member when the chamber member and the port member are welded together, and a cover member that covers the port member from a side opposite to the welded side between the chamber member and the port member. The intake groove has an outer wall surface opposing to the chamber member is formed with a reinforcing member so as to protrude from at least one of the port member side or chamber member side toward another one thereof, and the reinforcing member extends along an extending direction of the intake groove, the reinforcing member is welded to another reinforcing member protruding from another outer wall surface of the port member and chamber member, or from the port member and the chamber member.

Abstract: A seal member has a ring shape which is assembled in a portion between a tubular member to be inserted into and fixed to a mount hole formed to a head cover of an internal combustion engine and a peripheral wall portion of the mount hole. The seal member is provided with an axial-direction seal portion formed to axial one end portion of the seal member, and a diameter-direction seal portion formed to another one end of the seal member. A fixing member configured to fix movement in a diameter direction of the seal member between the axial-direction seal portion and the diameter-direction thereof is formed along a peripheral wall portion of the mount hole.