Intake manifold

An intake manifold formed by bonding a plurality of bonded parts (22, 23, 24, 24′) made of synthetic resin to one another, and including a surge tank (20, 20′) disposed sideways of an engine body (11), and a plurality of intake pipes (21A, 21B, 21C, 21D) disposed in parallel to one another and each having a rising pipe portion (29A, 29B, 29C, 29D) which is connected to a lower portion of said surge tank (20, 20′) on a side opposite from said engine body (11) and extends upwards, a space (38) being defined between said surge tank (20) and each of said rising pipe portions (29A to 29D), as viewed sideways in a direction parallel to a direction (28) of arrangement of said intake pipes (21A to 21D),

• characterized in that said surge tank (20, 20′) includes a main tank portion (20a) extending in the direction (28) of arrangement of said intake pipes (21A to 21D) and opposed to the rising pipe portions (29A to 29D) of said intake pipes (21A to 21D), and a sideways-bulged portion (20b) which is bulged to a side opposite from said engine body (11) from an intermediate portion of said main tank portion (20a) as viewed in said arrangement direction (28) to form a cross-sectional T-shape by cooperation with said main tank portion (20a), said sideways bulged portion being interposed between the rising pipe portions (29B, 29C) of a pair of the intake pipes (21B, 21C) disposed at the intermediate portion as viewed in said arrangement direction (28), and inner ends of a pair of spaces (38) defined respectively between the rising pipe portions (29A to 29D) of said intake pipes (21A to 21D) and said main tank portion (20a) on opposite sides of said sideways-bulged portion (20b) are closed by opposite sidewalls of said sideways-bulged portion (20b).