Intake manifold

An intake manifold formed of resin with a throttle valve mounting portion to which a throttle body is mounted, a surge tank, intake passages communicating with intake ports of a multi-cylinder engine in a one-to-one relationship, and engine-side mounting portions mounted to an engine side, arranged and connected in sequence downstream in intake air flow directions, the intake manifold comprising:

• segments including an upper member, a lower member, and a middle member that is interposed between the upper member and the lower member to demarcate and form the intake passages so that the intake passages are arranged in a straight line;
• and
• first welded portions at which the upper member and the middle member are welded together, and second welded portions at which the middle member and the lower member are welded together,
• the first welded portions being extended outward from one of the intake passages formed by the upper member and the middle member,
• the second welded portions being extended outward from the other one of the intake passages formed by the middle member and the lower member,
• the middle member being provided with at least one rib holding the first welded portions and the second welded portions in one piece.