Intake Manifold

The invention provides an intake manifold. Reducing the pressure fluctuation in the gas collecting chamber and suppressing variations in the auxiliary gas concentration distributed from the gas distributing part to the respective branch pipes. A intake manifold (1) includes a surge tank (2), a plurality of branch pipes (3C), and a gas distributor (8) for distributing auxiliary gas. The gas distribution unit (8) includes a gas introduction pipe for auxiliary gas, a gas collecting chamber (12) for gathering auxiliary gas from the gas introduction pipe, a plurality of gases branched from the samechamber (12) and connected to the branch pipes (3C) and a distribution passage (13C). Each gas distribution passage (13C) is a gas distribution chamber (14C) with an enlarged volume. A gas introduction hole (15C) for auxiliary gas is provided between each gas distribution chamber (14C) and the gas collection chamber (12), and an oulet hole (16C) for supplying auxiliary gas to each branch pipe (3C) is provided between eac